Make ViewComponentTagHelper use extension intermediate nodes

src/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X/IViewComponentTagHelperTargetExtension.cs

@@ -0,0 +1,12 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X
+{
+    public interface IViewComponentTagHelperTargetExtension : ICodeTargetExtension
+    {
+        void WriteViewComponentTagHelper(CodeRenderingContext context, ViewComponentTagHelperIntermediateNode node);
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X/RazorExtensions.cs

@@ -38,6 +38,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X
             EnsureDesignTime(builder);
 
             builder.Features.Add(new ViewComponentTagHelperPass());
+            builder.AddTargetExtension(new ViewComponentTagHelperTargetExtension());
         }
 
         private static void EnsureDesignTime(IRazorEngineBuilder builder)

src/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X/ViewComponentTagHelperIntermediateNode.cs

@@ -0,0 +1,51 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+using Microsoft.AspNetCore.Razor.Language.Intermediate;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X
+{
+    public sealed class ViewComponentTagHelperIntermediateNode : ExtensionIntermediateNode
+    {
+        public override IntermediateNodeCollection Children { get; } = IntermediateNodeCollection.ReadOnly;
+
+        public string ClassName { get; set; }
+
+        public TagHelperDescriptor TagHelper { get; set; }
+
+        public override void Accept(IntermediateNodeVisitor visitor)
+        {
+            if (visitor == null)
+            {
+                throw new ArgumentNullException(nameof(visitor));
+            }
+
+            AcceptExtensionNode<ViewComponentTagHelperIntermediateNode>(this, visitor);
+        }
+
+        public override void WriteNode(CodeTarget target, CodeRenderingContext context)
+        {
+            if (target == null)
+            {
+                throw new ArgumentNullException(nameof(target));
+            }
+
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            var extension = target.GetExtension<IViewComponentTagHelperTargetExtension>();
+            if (extension == null)
+            {
+                ReportMissingCodeTargetExtension<IViewComponentTagHelperTargetExtension>(context);
+                return;
+            }
+
+            extension.WriteViewComponentTagHelper(context, this);
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X/ViewComponentTagHelperPass.cs

@@ -1,13 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
 using System.Collections.Generic;
-using System.Diagnostics;
-using System.Linq;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
-using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 using Microsoft.AspNetCore.Razor.Language.Extensions;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 
@@ -18,8 +13,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X
         // Run after the default taghelper pass
         public override int Order => IntermediateNodePassBase.DefaultFeatureOrder + 2000;
 
-        private static readonly string[] PublicModifiers = new[] { "public" };
-
         protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
         {
             var @namespace = documentNode.FindPrimaryNamespace();
@@ -142,145 +135,13 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X
 
         private void AddTagHelperClass(Context context, TagHelperDescriptor tagHelper)
         {
-            var writer = new CodeWriter();
+            var node = new ViewComponentTagHelperIntermediateNode()
-            WriteClass(context, writer, tagHelper);
-
-            var code = new CSharpCodeIntermediateNode();
-            code.Children.Add(new IntermediateToken()
             {
-                Kind = TokenKind.CSharp,
+                ClassName = context.GetClassName(tagHelper),
-                Content = writer.GenerateCode()
+                TagHelper = tagHelper
-            });
+            };
 
-            context.Class.Children.Add(code);
+            context.Class.Children.Add(node);
-        }
-
-        private void WriteClass(Context context, CodeWriter writer, TagHelperDescriptor tagHelper)
-        {
-            // Add target element.
-            BuildTargetElementString(writer, tagHelper);
-
-            // Initialize declaration.
-            var tagHelperTypeName = "Microsoft.AspNetCore.Razor.TagHelpers.TagHelper";
-            var className = context.GetClassName(tagHelper);
-
-            using (writer.BuildClassDeclaration(PublicModifiers, className, tagHelperTypeName, interfaces: null))
-            {
-                // Add view component helper.
-                writer.WriteVariableDeclaration(
-                    $"private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper",
-                    "_helper",
-                    value: null);
-
-                // Add constructor.
-                BuildConstructorString(writer, className);
-
-                // Add attributes.
-                BuildAttributeDeclarations(writer, tagHelper);
-
-                // Add process method.
-                BuildProcessMethodString(writer, tagHelper);
-            }
-        }
-
-        private void BuildConstructorString(CodeWriter writer, string className)
-        {
-            writer.Write("public ")
-                .Write(className)
-                .Write("(")
-                .Write("global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper")
-                .WriteLine(")");
-            using (writer.BuildScope())
-            {
-                writer.WriteStartAssignment("_helper")
-                    .Write("helper")
-                    .WriteLine(";");
-            }
-        }
-
-        private void BuildAttributeDeclarations(CodeWriter writer, TagHelperDescriptor tagHelper)
-        {
-            writer.Write("[")
-              .Write("Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute")
-              .WriteParameterSeparator()
-              .Write($"global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute")
-              .WriteLine("]");
-
-            writer.WriteAutoPropertyDeclaration(
-                PublicModifiers,
-                $"global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext",
-                "ViewContext");
-
-            foreach (var attribute in tagHelper.BoundAttributes)
-            {
-                writer.WriteAutoPropertyDeclaration(
-                    PublicModifiers,
-                    attribute.TypeName,
-                    attribute.GetPropertyName());
-
-                if (attribute.IndexerTypeName != null)
-                {
-                    writer.Write(" = ")
-                        .WriteStartNewObject(attribute.TypeName)
-                        .WriteEndMethodInvocation();
-                }
-            }
-        }
-
-        private void BuildProcessMethodString(CodeWriter writer, TagHelperDescriptor tagHelper)
-        {
-            var contextVariable = "context";
-            var outputVariable = "output";
-
-            using (writer.BuildMethodDeclaration(
-                    $"public override async",
-                    $"global::{typeof(Task).FullName}",
-                    "ProcessAsync",
-                    new Dictionary<string, string>()
-                    {
-                        { "Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext", contextVariable },
-                        { "Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput", outputVariable }
-                    }))
-            {
-                writer.WriteInstanceMethodInvocation(
-                    $"(_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?",
-                    "Contextualize",
-                    new[] { "ViewContext" });
-
-                var methodParameters = GetMethodParameters(tagHelper);
-                var contentVariable = "content";
-                writer.Write("var ")
-                    .WriteStartAssignment(contentVariable)
-                    .WriteInstanceMethodInvocation($"await _helper", "InvokeAsync", methodParameters);
-                writer.WriteStartAssignment($"{outputVariable}.TagName")
-                    .WriteLine("null;");
-                writer.WriteInstanceMethodInvocation(
-                    $"{outputVariable}.Content",
-                    "SetHtmlContent",
-                    new[] { contentVariable });
-            }
-        }
-
-        private string[] GetMethodParameters(TagHelperDescriptor tagHelper)
-        {
-            var propertyNames = tagHelper.BoundAttributes.Select(attribute => attribute.GetPropertyName());
-            var joinedPropertyNames = string.Join(", ", propertyNames);
-            var parametersString = $"new {{ { joinedPropertyNames } }}";
-            var viewComponentName = tagHelper.GetViewComponentName();
-            var methodParameters = new[] { $"\"{viewComponentName}\"", parametersString };
-            return methodParameters;
-        }
-
-        private void BuildTargetElementString(CodeWriter writer, TagHelperDescriptor tagHelper)
-        {
-            Debug.Assert(tagHelper.TagMatchingRules.Count() == 1);
-
-            var rule = tagHelper.TagMatchingRules.First();
-
-            writer.Write("[")
-                .WriteStartMethodInvocation("Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute")
-                .WriteStringLiteral(rule.TagName)
-                .WriteLine(")]");
         }
 
         private struct Context

src/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X/ViewComponentTagHelperTargetExtension.cs

@@ -0,0 +1,178 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X
+{
+    internal class ViewComponentTagHelperTargetExtension : IViewComponentTagHelperTargetExtension
+    {
+        private static readonly string[] PublicModifiers = new[] { "public" };
+
+        public string TagHelperTypeName { get; set; } = "Microsoft.AspNetCore.Razor.TagHelpers.TagHelper";
+
+        public string ViewComponentHelperTypeName { get; set; } = "global::Microsoft.AspNetCore.Mvc.IViewComponentHelper";
+
+        public string ViewComponentHelperVariableName { get; set; } = "_helper";
+
+        public string ViewComponentInvokeMethodName { get; set; } = "InvokeAsync";
+
+        public string HtmlAttributeNotBoundAttributeTypeName { get; set; } = "Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute";
+
+        public string ViewContextAttributeTypeName { get; set; } = "global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute";
+
+        public string ViewContextTypeName { get; set; } = "global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext";
+
+        public string ViewContextPropertyName { get; set; } = "ViewContext";
+
+        public string HtmlTargetElementAttributeTypeName { get; set; } = "Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute";
+
+        public string TagHelperProcessMethodName { get; set; } = "ProcessAsync";
+
+        public string TagHelperContextTypeName { get; set; } = "Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext";
+
+        public string TagHelperContextVariableName { get; set; } = "context";
+
+        public string TagHelperOutputTypeName { get; set; } = "Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput";
+
+        public string TagHelperOutputVariableName { get; set; } = "output";
+
+        public string TagHelperOutputTagNamePropertyName { get; set; } = "TagName";
+
+        public string TagHelperOutputContentPropertyName { get; set; } = "Content";
+
+        public string TagHelperContentSetMethodName { get; set; } = "SetHtmlContent";
+
+        public string TagHelperContentVariableName { get; set; } = "content";
+
+        public string IViewContextAwareTypeName { get; set; } = "global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware";
+
+        public string IViewContextAwareContextualizeMethodName { get; set; } = "Contextualize";
+
+        public void WriteViewComponentTagHelper(CodeRenderingContext context, ViewComponentTagHelperIntermediateNode node)
+        {
+            // Add target element.
+            WriteTargetElementString(context.CodeWriter, node.TagHelper);
+
+            // Initialize declaration.
+            using (context.CodeWriter.BuildClassDeclaration(PublicModifiers, node.ClassName, TagHelperTypeName, interfaces: null))
+            {
+                // Add view component helper.
+                context.CodeWriter.WriteVariableDeclaration(
+                    $"private readonly {ViewComponentHelperTypeName}",
+                    ViewComponentHelperVariableName,
+                    value: null);
+
+                // Add constructor.
+                WriteConstructorString(context.CodeWriter, node.ClassName);
+
+                // Add attributes.
+                WriteAttributeDeclarations(context.CodeWriter, node.TagHelper);
+
+                // Add process method.
+                WriteProcessMethodString(context.CodeWriter, node.TagHelper);
+            }
+        }
+
+        private void WriteConstructorString(CodeWriter writer, string className)
+        {
+            writer.Write("public ")
+                .Write(className)
+                .Write("(")
+                .Write($"{ViewComponentHelperTypeName} helper")
+                .WriteLine(")");
+            using (writer.BuildScope())
+            {
+                writer.WriteStartAssignment(ViewComponentHelperVariableName)
+                    .Write("helper")
+                    .WriteLine(";");
+            }
+        }
+
+        private void WriteAttributeDeclarations(CodeWriter writer, TagHelperDescriptor tagHelper)
+        {
+            writer.Write("[")
+              .Write(HtmlAttributeNotBoundAttributeTypeName)
+              .WriteParameterSeparator()
+              .Write(ViewContextAttributeTypeName)
+              .WriteLine("]");
+
+            writer.WriteAutoPropertyDeclaration(
+                PublicModifiers,
+                ViewContextTypeName,
+                ViewContextPropertyName);
+
+            foreach (var attribute in tagHelper.BoundAttributes)
+            {
+                writer.WriteAutoPropertyDeclaration(
+                    PublicModifiers,
+                    attribute.TypeName,
+                    attribute.GetPropertyName());
+
+                if (attribute.IndexerTypeName != null)
+                {
+                    writer.Write(" = ")
+                        .WriteStartNewObject(attribute.TypeName)
+                        .WriteEndMethodInvocation();
+                }
+            }
+        }
+
+        private void WriteProcessMethodString(CodeWriter writer, TagHelperDescriptor tagHelper)
+        {
+            using (writer.BuildMethodDeclaration(
+                    $"public override async",
+                    $"global::{typeof(Task).FullName}",
+                    TagHelperProcessMethodName,
+                    new Dictionary<string, string>()
+                    {
+                        { TagHelperContextTypeName, TagHelperContextVariableName },
+                        { TagHelperOutputTypeName, TagHelperOutputVariableName }
+                    }))
+            {
+                writer.WriteInstanceMethodInvocation(
+                    $"({ViewComponentHelperVariableName} as {IViewContextAwareTypeName})?",
+                    IViewContextAwareContextualizeMethodName,
+                    new[] { ViewContextPropertyName });
+
+                var methodParameters = GetMethodParameters(tagHelper);
+                writer.Write("var ")
+                    .WriteStartAssignment(TagHelperContentVariableName)
+                    .WriteInstanceMethodInvocation($"await {ViewComponentHelperVariableName}", ViewComponentInvokeMethodName, methodParameters);
+                writer.WriteStartAssignment($"{TagHelperOutputVariableName}.{TagHelperOutputTagNamePropertyName}")
+                    .WriteLine("null;");
+                writer.WriteInstanceMethodInvocation(
+                    $"{TagHelperOutputVariableName}.{TagHelperOutputContentPropertyName}",
+                    TagHelperContentSetMethodName,
+                    new[] { TagHelperContentVariableName });
+            }
+        }
+
+        private string[] GetMethodParameters(TagHelperDescriptor tagHelper)
+        {
+            var propertyNames = tagHelper.BoundAttributes.Select(attribute => attribute.GetPropertyName());
+            var joinedPropertyNames = string.Join(", ", propertyNames);
+            var parametersString = $"new {{ { joinedPropertyNames } }}";
+            var viewComponentName = tagHelper.GetViewComponentName();
+            var methodParameters = new[] { $"\"{viewComponentName}\"", parametersString };
+            return methodParameters;
+        }
+
+        private void WriteTargetElementString(CodeWriter writer, TagHelperDescriptor tagHelper)
+        {
+            Debug.Assert(tagHelper.TagMatchingRules.Count() == 1);
+
+            var rule = tagHelper.TagMatchingRules.First();
+
+            writer.Write("[")
+                .WriteStartMethodInvocation(HtmlTargetElementAttributeTypeName)
+                .WriteStringLiteral(rule.TagName)
+                .WriteLine(")]");
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/IViewComponentTagHelperTargetExtension.cs

@@ -0,0 +1,12 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
+{
+    public interface IViewComponentTagHelperTargetExtension : ICodeTargetExtension
+    {
+        void WriteViewComponentTagHelper(CodeRenderingContext context, ViewComponentTagHelperIntermediateNode node);
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/RazorExtensions.cs

@@ -19,6 +19,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             InheritsDirective.Register(builder);
             SectionDirective.Register(builder);
 
+            builder.AddTargetExtension(new ViewComponentTagHelperTargetExtension());
             builder.AddTargetExtension(new TemplateTargetExtension()
             {
                 TemplateTypeName = "global::Microsoft.AspNetCore.Mvc.Razor.HelperResult",

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/ViewComponentTagHelperIntermediateNode.cs

@@ -0,0 +1,51 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+using Microsoft.AspNetCore.Razor.Language.Intermediate;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
+{
+    public sealed class ViewComponentTagHelperIntermediateNode : ExtensionIntermediateNode
+    {
+        public override IntermediateNodeCollection Children { get; } = IntermediateNodeCollection.ReadOnly;
+
+        public string ClassName { get; set; }
+
+        public TagHelperDescriptor TagHelper { get; set; }
+
+        public override void Accept(IntermediateNodeVisitor visitor)
+        {
+            if (visitor == null)
+            {
+                throw new ArgumentNullException(nameof(visitor));
+            }
+
+            AcceptExtensionNode<ViewComponentTagHelperIntermediateNode>(this, visitor);
+        }
+
+        public override void WriteNode(CodeTarget target, CodeRenderingContext context)
+        {
+            if (target == null)
+            {
+                throw new ArgumentNullException(nameof(target));
+            }
+
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            var extension = target.GetExtension<IViewComponentTagHelperTargetExtension>();
+            if (extension == null)
+            {
+                ReportMissingCodeTargetExtension<IViewComponentTagHelperTargetExtension>(context);
+                return;
+            }
+
+            extension.WriteViewComponentTagHelper(context, this);
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/ViewComponentTagHelperPass.cs

@@ -1,13 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
 using System.Collections.Generic;
-using System.Diagnostics;
-using System.Linq;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
-using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 using Microsoft.AspNetCore.Razor.Language.Extensions;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 
@@ -18,8 +13,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
         // Run after the default taghelper pass
         public override int Order => IntermediateNodePassBase.DefaultFeatureOrder + 2000;
 
-        private static readonly string[] PublicModifiers = new[] { "public" };
-
         protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
         {
             var @namespace = documentNode.FindPrimaryNamespace();
@@ -142,145 +135,13 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
 
         private void AddTagHelperClass(Context context, TagHelperDescriptor tagHelper)
         {
-            var writer = new CodeWriter();
+            var node = new ViewComponentTagHelperIntermediateNode()
-            WriteClass(context, writer, tagHelper);
-
-            var code = new CSharpCodeIntermediateNode();
-            code.Children.Add(new IntermediateToken()
             {
-                Kind = TokenKind.CSharp,
+                ClassName = context.GetClassName(tagHelper),
-                Content = writer.GenerateCode()
+                TagHelper = tagHelper
-            });
+            };
 
-            context.Class.Children.Add(code);
+            context.Class.Children.Add(node);
-        }
-
-        private void WriteClass(Context context, CodeWriter writer, TagHelperDescriptor tagHelper)
-        {
-            // Add target element.
-            BuildTargetElementString(writer, tagHelper);
-
-            // Initialize declaration.
-            var tagHelperTypeName = "Microsoft.AspNetCore.Razor.TagHelpers.TagHelper";
-            var className = context.GetClassName(tagHelper);
-
-            using (writer.BuildClassDeclaration(PublicModifiers, className, tagHelperTypeName, interfaces: null))
-            {
-                // Add view component helper.
-                writer.WriteVariableDeclaration(
-                    $"private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper",
-                    "_helper",
-                    value: null);
-
-                // Add constructor.
-                BuildConstructorString(writer, className);
-
-                // Add attributes.
-                BuildAttributeDeclarations(writer, tagHelper);
-
-                // Add process method.
-                BuildProcessMethodString(writer, tagHelper);
-            }
-        }
-
-        private void BuildConstructorString(CodeWriter writer, string className)
-        {
-            writer.Write("public ")
-                .Write(className)
-                .Write("(")
-                .Write("global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper")
-                .WriteLine(")");
-            using (writer.BuildScope())
-            {
-                writer.WriteStartAssignment("_helper")
-                    .Write("helper")
-                    .WriteLine(";");
-            }
-        }
-
-        private void BuildAttributeDeclarations(CodeWriter writer, TagHelperDescriptor tagHelper)
-        {
-            writer.Write("[")
-              .Write("Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute")
-              .WriteParameterSeparator()
-              .Write($"global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute")
-              .WriteLine("]");
-
-            writer.WriteAutoPropertyDeclaration(
-                PublicModifiers,
-                $"global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext",
-                "ViewContext");
-
-            foreach (var attribute in tagHelper.BoundAttributes)
-            {
-                writer.WriteAutoPropertyDeclaration(
-                    PublicModifiers,
-                    attribute.TypeName,
-                    attribute.GetPropertyName());
-
-                if (attribute.IndexerTypeName != null)
-                {
-                    writer.Write(" = ")
-                        .WriteStartNewObject(attribute.TypeName)
-                        .WriteEndMethodInvocation();
-                }
-            }
-        }
-
-        private void BuildProcessMethodString(CodeWriter writer, TagHelperDescriptor tagHelper)
-        {
-            var contextVariable = "context";
-            var outputVariable = "output";
-
-            using (writer.BuildMethodDeclaration(
-                    $"public override async",
-                    $"global::{typeof(Task).FullName}",
-                    "ProcessAsync",
-                    new Dictionary<string, string>()
-                    {
-                        { "Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext", contextVariable },
-                        { "Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput", outputVariable }
-                    }))
-            {
-                writer.WriteInstanceMethodInvocation(
-                    $"(_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?",
-                    "Contextualize",
-                    new[] { "ViewContext" });
-
-                var methodParameters = GetMethodParameters(tagHelper);
-                var contentVariable = "content";
-                writer.Write("var ")
-                    .WriteStartAssignment(contentVariable)
-                    .WriteInstanceMethodInvocation($"await _helper", "InvokeAsync", methodParameters);
-                writer.WriteStartAssignment($"{outputVariable}.TagName")
-                    .WriteLine("null;");
-                writer.WriteInstanceMethodInvocation(
-                    $"{outputVariable}.Content",
-                    "SetHtmlContent",
-                    new[] { contentVariable });
-            }
-        }
-
-        private string[] GetMethodParameters(TagHelperDescriptor tagHelper)
-        {
-            var propertyNames = tagHelper.BoundAttributes.Select(attribute => attribute.GetPropertyName());
-            var joinedPropertyNames = string.Join(", ", propertyNames);
-            var parametersString = $"new {{ { joinedPropertyNames } }}";
-            var viewComponentName = tagHelper.GetViewComponentName();
-            var methodParameters = new[] { $"\"{viewComponentName}\"", parametersString };
-            return methodParameters;
-        }
-
-        private void BuildTargetElementString(CodeWriter writer, TagHelperDescriptor tagHelper)
-        {
-            Debug.Assert(tagHelper.TagMatchingRules.Count() == 1);
-
-            var rule = tagHelper.TagMatchingRules.First();
-
-            writer.Write("[")
-                .WriteStartMethodInvocation("Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute")
-                .WriteStringLiteral(rule.TagName)
-                .WriteLine(")]");
         }
 
         private struct Context

src/Microsoft.AspNetCore.Mvc.Razor.Extensions/ViewComponentTagHelperTargetExtension.cs

@@ -0,0 +1,178 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
+{
+    internal class ViewComponentTagHelperTargetExtension : IViewComponentTagHelperTargetExtension
+    {
+        private static readonly string[] PublicModifiers = new[] { "public" };
+
+        public string TagHelperTypeName { get; set; } = "Microsoft.AspNetCore.Razor.TagHelpers.TagHelper";
+
+        public string ViewComponentHelperTypeName { get; set; } = "global::Microsoft.AspNetCore.Mvc.IViewComponentHelper";
+
+        public string ViewComponentHelperVariableName { get; set; } = "_helper";
+
+        public string ViewComponentInvokeMethodName { get; set; } = "InvokeAsync";
+
+        public string HtmlAttributeNotBoundAttributeTypeName { get; set; } = "Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute";
+
+        public string ViewContextAttributeTypeName { get; set; } = "global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute";
+
+        public string ViewContextTypeName { get; set; } = "global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext";
+
+        public string ViewContextPropertyName { get; set; } = "ViewContext";
+
+        public string HtmlTargetElementAttributeTypeName { get; set; } = "Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute";
+
+        public string TagHelperProcessMethodName { get; set; } = "ProcessAsync";
+
+        public string TagHelperContextTypeName { get; set; } = "Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext";
+
+        public string TagHelperContextVariableName { get; set; } = "context";
+
+        public string TagHelperOutputTypeName { get; set; } = "Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput";
+
+        public string TagHelperOutputVariableName { get; set; } = "output";
+
+        public string TagHelperOutputTagNamePropertyName { get; set; } = "TagName";
+
+        public string TagHelperOutputContentPropertyName { get; set; } = "Content";
+
+        public string TagHelperContentSetMethodName { get; set; } = "SetHtmlContent";
+
+        public string TagHelperContentVariableName { get; set; } = "content";
+
+        public string IViewContextAwareTypeName { get; set; } = "global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware";
+
+        public string IViewContextAwareContextualizeMethodName { get; set; } = "Contextualize";
+
+        public void WriteViewComponentTagHelper(CodeRenderingContext context, ViewComponentTagHelperIntermediateNode node)
+        {
+            // Add target element.
+            WriteTargetElementString(context.CodeWriter, node.TagHelper);
+
+            // Initialize declaration.
+            using (context.CodeWriter.BuildClassDeclaration(PublicModifiers, node.ClassName, TagHelperTypeName, interfaces: null))
+            {
+                // Add view component helper.
+                context.CodeWriter.WriteVariableDeclaration(
+                    $"private readonly {ViewComponentHelperTypeName}",
+                    ViewComponentHelperVariableName,
+                    value: null);
+
+                // Add constructor.
+                WriteConstructorString(context.CodeWriter, node.ClassName);
+
+                // Add attributes.
+                WriteAttributeDeclarations(context.CodeWriter, node.TagHelper);
+
+                // Add process method.
+                WriteProcessMethodString(context.CodeWriter, node.TagHelper);
+            }
+        }
+
+        private void WriteConstructorString(CodeWriter writer, string className)
+        {
+            writer.Write("public ")
+                .Write(className)
+                .Write("(")
+                .Write($"{ViewComponentHelperTypeName} helper")
+                .WriteLine(")");
+            using (writer.BuildScope())
+            {
+                writer.WriteStartAssignment(ViewComponentHelperVariableName)
+                    .Write("helper")
+                    .WriteLine(";");
+            }
+        }
+
+        private void WriteAttributeDeclarations(CodeWriter writer, TagHelperDescriptor tagHelper)
+        {
+            writer.Write("[")
+              .Write(HtmlAttributeNotBoundAttributeTypeName)
+              .WriteParameterSeparator()
+              .Write(ViewContextAttributeTypeName)
+              .WriteLine("]");
+
+            writer.WriteAutoPropertyDeclaration(
+                PublicModifiers,
+                ViewContextTypeName,
+                ViewContextPropertyName);
+
+            foreach (var attribute in tagHelper.BoundAttributes)
+            {
+                writer.WriteAutoPropertyDeclaration(
+                    PublicModifiers,
+                    attribute.TypeName,
+                    attribute.GetPropertyName());
+
+                if (attribute.IndexerTypeName != null)
+                {
+                    writer.Write(" = ")
+                        .WriteStartNewObject(attribute.TypeName)
+                        .WriteEndMethodInvocation();
+                }
+            }
+        }
+
+        private void WriteProcessMethodString(CodeWriter writer, TagHelperDescriptor tagHelper)
+        {
+            using (writer.BuildMethodDeclaration(
+                    $"public override async",
+                    $"global::{typeof(Task).FullName}",
+                    TagHelperProcessMethodName,
+                    new Dictionary<string, string>()
+                    {
+                        { TagHelperContextTypeName, TagHelperContextVariableName },
+                        { TagHelperOutputTypeName, TagHelperOutputVariableName }
+                    }))
+            {
+                writer.WriteInstanceMethodInvocation(
+                    $"({ViewComponentHelperVariableName} as {IViewContextAwareTypeName})?",
+                    IViewContextAwareContextualizeMethodName,
+                    new[] { ViewContextPropertyName });
+
+                var methodParameters = GetMethodParameters(tagHelper);
+                writer.Write("var ")
+                    .WriteStartAssignment(TagHelperContentVariableName)
+                    .WriteInstanceMethodInvocation($"await {ViewComponentHelperVariableName}", ViewComponentInvokeMethodName, methodParameters);
+                writer.WriteStartAssignment($"{TagHelperOutputVariableName}.{TagHelperOutputTagNamePropertyName}")
+                    .WriteLine("null;");
+                writer.WriteInstanceMethodInvocation(
+                    $"{TagHelperOutputVariableName}.{TagHelperOutputContentPropertyName}",
+                    TagHelperContentSetMethodName,
+                    new[] { TagHelperContentVariableName });
+            }
+        }
+
+        private string[] GetMethodParameters(TagHelperDescriptor tagHelper)
+        {
+            var propertyNames = tagHelper.BoundAttributes.Select(attribute => attribute.GetPropertyName());
+            var joinedPropertyNames = string.Join(", ", propertyNames);
+            var parametersString = $"new {{ { joinedPropertyNames } }}";
+            var viewComponentName = tagHelper.GetViewComponentName();
+            var methodParameters = new[] { $"\"{viewComponentName}\"", parametersString };
+            return methodParameters;
+        }
+
+        private void WriteTargetElementString(CodeWriter writer, TagHelperDescriptor tagHelper)
+        {
+            Debug.Assert(tagHelper.TagMatchingRules.Count() == 1);
+
+            var rule = tagHelper.TagMatchingRules.First();
+
+            writer.Write("[")
+                .WriteStartMethodInvocation(HtmlTargetElementAttributeTypeName)
+                .WriteStringLiteral(rule.TagName)
+                .WriteLine(")]");
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/ViewComponentTagHelper_DesignTime.codegen.cs

@@ -57,25 +57,24 @@ global::System.Object __typeHelper = "*, AppCode";
         [global::Microsoft.AspNetCore.Mvc.Razor.Internal.RazorInjectAttribute]
         public global::Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper<dynamic> Html { get; private set; }
         [Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute("vc:test")]
-public class __Generated__TestViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
+        public class __Generated__TestViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
+        {
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
+            private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
-    public __Generated__TestViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
+            public __Generated__TestViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
-    {
+            {
-        _helper = helper;
+                _helper = helper;
-    }
+            }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
+            [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
+            public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.String firstName { get; set; }
+            public System.String firstName { get; set; }
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
+            public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
+            {
-        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
+                (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var content = await _helper.InvokeAsync("Test", new { firstName });
+                var content = await _helper.InvokeAsync("Test", new { firstName });
-        output.TagName = null;
+                output.TagName = null;
-        output.Content.SetHtmlContent(content);
+                output.Content.SetHtmlContent(content);
-    }
+            }
-}
+        }
-
     }
 }
 #pragma warning restore 1591

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/ViewComponentTagHelper_DesignTime.ir.txt

@@ -56,5 +56,4 @@ Document -
             Inject - 
             Inject - 
             Inject - 
-            CSharpCode - 
+            ViewComponentTagHelper - 
-                IntermediateToken -  - CSharp - [Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute("vc:test")]\npublic class __Generated__TestViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper\n{\n    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;\n    public __Generated__TestViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)\n    {\n        _helper = helper;\n    }\n    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]\n    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }\n    public System.String firstName { get; set; }\n    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)\n    {\n        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);\n        var content = await _helper.InvokeAsync("Test", new { firstName });\n        output.TagName = null;\n        output.Content.SetHtmlContent(content);\n    }\n}\n

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/ViewComponentTagHelper_Runtime.codegen.cs

@@ -87,25 +87,24 @@ namespace AspNetCore
         [global::Microsoft.AspNetCore.Mvc.Razor.Internal.RazorInjectAttribute]
         public global::Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper<dynamic> Html { get; private set; }
         [Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute("vc:test")]
-public class __Generated__TestViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
+        public class __Generated__TestViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
+        {
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
+            private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
-    public __Generated__TestViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
+            public __Generated__TestViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
-    {
+            {
-        _helper = helper;
+                _helper = helper;
-    }
+            }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
+            [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
+            public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.String firstName { get; set; }
+            public System.String firstName { get; set; }
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
+            public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
+            {
-        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
+                (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var content = await _helper.InvokeAsync("Test", new { firstName });
+                var content = await _helper.InvokeAsync("Test", new { firstName });
-        output.TagName = null;
+                output.TagName = null;
-        output.Content.SetHtmlContent(content);
+                output.Content.SetHtmlContent(content);
-    }
+            }
-}
+        }
-
     }
 }
 #pragma warning restore 1591

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/ViewComponentTagHelper_Runtime.ir.txt

@@ -41,5 +41,4 @@ Document -
             Inject - 
             Inject - 
             Inject - 
-            CSharpCode - 
+            ViewComponentTagHelper - 
-                IntermediateToken -  - CSharp - [Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute("vc:test")]\npublic class __Generated__TestViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper\n{\n    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;\n    public __Generated__TestViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)\n    {\n        _helper = helper;\n    }\n    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]\n    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }\n    public System.String firstName { get; set; }\n    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)\n    {\n        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);\n        var content = await _helper.InvokeAsync("Test", new { firstName });\n        output.TagName = null;\n        output.Content.SetHtmlContent(content);\n    }\n}\n

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/ViewComponentTagHelperPassTest.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Linq;
-using System.Text;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Extensions;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
@@ -47,7 +46,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             Assert.Equal(3, @class.Children.Count); // No class node created for a VCTH
             for (var i = 0; i < @class.Children.Count; i++)
             {
-                Assert.IsNotType<CSharpCodeIntermediateNode>(@class.Children[i]);
+                Assert.IsNotType<ViewComponentTagHelperIntermediateNode>(@class.Children[i]);
             }
         }
 
@@ -94,32 +93,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
             var @class = FindClassNode(irDocument);
             Assert.Equal(4, @class.Children.Count);
 
-            var vcthClass = Assert.IsType<CSharpCodeIntermediateNode>(@class.Children.Last());
+            Assert.IsType<ViewComponentTagHelperIntermediateNode>(@class.Children.Last());
-            var tokenNode = vcthClass.Children[0] as IntermediateToken;
-            Assert.Equal(
-                @"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
-public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
-    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
-    {
-        _helper = helper;
-    }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.Int32 Foo { get; set; }
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
-        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var content = await _helper.InvokeAsync(""TagCloud"", new { Foo });
-        output.TagName = null;
-        output.Content.SetHtmlContent(content);
-    }
-}
-",
-                tokenNode.Content,
-                ignoreLineEndingDifferences: true);
-            Assert.Equal(TokenKind.CSharp, tokenNode.Kind);
         }
 
         [Fact]
@@ -165,33 +139,7 @@ public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.
             var @class = FindClassNode(irDocument);
             Assert.Equal(4, @class.Children.Count);
 
-            var vcthClass = Assert.IsType<CSharpCodeIntermediateNode>(@class.Children[3]);
+            Assert.IsType<ViewComponentTagHelperIntermediateNode>(@class.Children[3]);
-            var tokenNode = vcthClass.Children[0] as IntermediateToken;
-            Assert.Equal(
-                @"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
-public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
-    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
-    {
-        _helper = helper;
-    }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.Collections.Generic.Dictionary<System.String, System.Int32> Tags { get; set; }
-     = new System.Collections.Generic.Dictionary<System.String, System.Int32>();
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
-        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var content = await _helper.InvokeAsync(""TagCloud"", new { Tags });
-        output.TagName = null;
-        output.Content.SetHtmlContent(content);
-    }
-}
-",
-                tokenNode.Content,
-                ignoreLineEndingDifferences: true);
-            Assert.Equal(TokenKind.CSharp, tokenNode.Kind);
         }
 
         [Fact]
@@ -249,32 +197,7 @@ public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.
             var @class = FindClassNode(irDocument);
             Assert.Equal(5, @class.Children.Count);
 
-            var vcthClass = Assert.IsType<CSharpCodeIntermediateNode>(@class.Children.Last());
+            Assert.IsType<ViewComponentTagHelperIntermediateNode>(@class.Children.Last());
-            var tokenNode = vcthClass.Children[0] as IntermediateToken;
-            Assert.Equal(
-                @"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
-public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
-    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
-    {
-        _helper = helper;
-    }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.Int32 Foo { get; set; }
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
-        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var content = await _helper.InvokeAsync(""TagCloud"", new { Foo });
-        output.TagName = null;
-        output.Content.SetHtmlContent(content);
-    }
-}
-",
-                tokenNode.Content,
-                ignoreLineEndingDifferences: true);
-            Assert.Equal(TokenKind.CSharp, tokenNode.Kind);
         }
 
         private RazorCodeDocument CreateDocument(string content)
@@ -329,21 +252,6 @@ public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.
             return visitor.Node;
         }
 
-        private string GetCSharpContent(IntermediateNode node)
-        {
-            var builder = new StringBuilder();
-            for (var i = 0; i < node.Children.Count; i++)
-            {
-                var child = node.Children[i] as IntermediateToken;
-                if (child.Kind == TokenKind.CSharp)
-                {
-                    builder.Append(child.Content);
-                }
-            }
-
-            return builder.ToString();
-        }
-
         private class ClassDeclarationNodeVisitor : IntermediateNodeWalker
         {
             public ClassDeclarationIntermediateNode Node { get; set; }

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Test/ViewComponentTagHelperTargetExtensionTest.cs

@@ -0,0 +1,120 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Extensions
+{
+    public class ViewComponentTagHelperTargetExtensionTest
+    {
+        [Fact]
+        public void WriteViewComponentTagHelper_GeneratesViewComponentTagHelper()
+        {
+            // Arrange
+            var tagHelper = TagHelperDescriptorBuilder
+                .Create(ViewComponentTagHelperConventions.Kind, "TestTagHelper", "TestAssembly")
+                .TypeName("__Generated__TagCloudViewComponentTagHelper")
+                .BoundAttributeDescriptor(attribute => attribute
+                    .Name("Foo")
+                    .TypeName("System.Int32")
+                    .PropertyName("Foo"))
+                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("tagcloud"))
+                .AddMetadata(ViewComponentTagHelperMetadata.Name, "TagCloud")
+                .Build();
+
+            var extension = new ViewComponentTagHelperTargetExtension();
+            var context = TestCodeRenderingContext.CreateRuntime();
+            var node = new ViewComponentTagHelperIntermediateNode()
+            {
+                ClassName = "__Generated__TagCloudViewComponentTagHelper",
+                TagHelper = tagHelper
+            };
+
+            // Act
+            extension.WriteViewComponentTagHelper(context, node);
+
+            // Assert
+            var csharp = context.CodeWriter.GenerateCode();
+            Assert.Equal(
+                @"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
+public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
+{
+    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
+    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
+    {
+        _helper = helper;
+    }
+    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
+    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
+    public System.Int32 Foo { get; set; }
+    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
+    {
+        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
+        var content = await _helper.InvokeAsync(""TagCloud"", new { Foo });
+        output.TagName = null;
+        output.Content.SetHtmlContent(content);
+    }
+}
+",
+                csharp,
+                ignoreLineEndingDifferences: true);
+        }
+
+        [Fact]
+        public void WriteViewComponentTagHelper_GeneratesViewComponentTagHelper_WithIndexer()
+        {
+            // Arrange
+            var tagHelper = TagHelperDescriptorBuilder
+                .Create(ViewComponentTagHelperConventions.Kind, "TestTagHelper", "TestAssembly")
+                .TypeName("__Generated__TagCloudViewComponentTagHelper")
+                .BoundAttributeDescriptor(attribute => attribute
+                    .Name("Foo")
+                    .TypeName("System.Collections.Generic.Dictionary<System.String, System.Int32>")
+                    .PropertyName("Tags")
+                    .AsDictionaryAttribute("foo-", "System.Int32"))
+                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("tagcloud"))
+                .AddMetadata(ViewComponentTagHelperMetadata.Name, "TagCloud")
+                .Build();
+
+            var extension = new ViewComponentTagHelperTargetExtension();
+            var context = TestCodeRenderingContext.CreateRuntime();
+            var node = new ViewComponentTagHelperIntermediateNode()
+            {
+                ClassName = "__Generated__TagCloudViewComponentTagHelper",
+                TagHelper = tagHelper
+            };
+
+            // Act
+            extension.WriteViewComponentTagHelper(context, node);
+
+            // Assert
+            var csharp = context.CodeWriter.GenerateCode();
+            Assert.Equal(
+                @"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
+public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
+{
+    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
+    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
+    {
+        _helper = helper;
+    }
+    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
+    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
+    public System.Collections.Generic.Dictionary<System.String, System.Int32> Tags { get; set; }
+     = new System.Collections.Generic.Dictionary<System.String, System.Int32>();
+    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
+    {
+        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
+        var content = await _helper.InvokeAsync(""TagCloud"", new { Tags });
+        output.TagName = null;
+        output.Content.SetHtmlContent(content);
+    }
+}
+",
+                csharp,
+                ignoreLineEndingDifferences: true);
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/ViewComponentTagHelper_DesignTime.codegen.cs

@@ -57,25 +57,24 @@ global::System.Object __typeHelper = "*, AppCode";
         [global::Microsoft.AspNetCore.Mvc.Razor.Internal.RazorInjectAttribute]
         public global::Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper<dynamic> Html { get; private set; }
         [Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute("vc:test")]
-public class __Generated__TestViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
+        public class __Generated__TestViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
+        {
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
+            private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
-    public __Generated__TestViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
+            public __Generated__TestViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
-    {
+            {
-        _helper = helper;
+                _helper = helper;
-    }
+            }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
+            [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
+            public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.String firstName { get; set; }
+            public System.String firstName { get; set; }
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
+            public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
+            {
-        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
+                (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var content = await _helper.InvokeAsync("Test", new { firstName });
+                var content = await _helper.InvokeAsync("Test", new { firstName });
-        output.TagName = null;
+                output.TagName = null;
-        output.Content.SetHtmlContent(content);
+                output.Content.SetHtmlContent(content);
-    }
+            }
-}
+        }
-
     }
 }
 #pragma warning restore 1591

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/ViewComponentTagHelper_DesignTime.ir.txt

@@ -54,5 +54,4 @@ Document -
             Inject - 
             Inject - 
             Inject - 
-            CSharpCode - 
+            ViewComponentTagHelper - 
-                IntermediateToken -  - CSharp - [Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute("vc:test")]\npublic class __Generated__TestViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper\n{\n    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;\n    public __Generated__TestViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)\n    {\n        _helper = helper;\n    }\n    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]\n    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }\n    public System.String firstName { get; set; }\n    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)\n    {\n        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);\n        var content = await _helper.InvokeAsync("Test", new { firstName });\n        output.TagName = null;\n        output.Content.SetHtmlContent(content);\n    }\n}\n

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X.Test/ViewComponentTagHelperPassTest.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Linq;
-using System.Text;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Extensions;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
@@ -47,7 +46,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X
             Assert.Equal(3, @class.Children.Count); // No class node created for a VCTH
             for (var i = 0; i < @class.Children.Count; i++)
             {
-                Assert.IsNotType<CSharpCodeIntermediateNode>(@class.Children[i]);
+                Assert.IsNotType<ViewComponentTagHelperIntermediateNode>(@class.Children[i]);
             }
         }
 
@@ -94,32 +93,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X
             var @class = FindClassNode(irDocument);
             Assert.Equal(4, @class.Children.Count);
 
-            var vcthClass = Assert.IsType<CSharpCodeIntermediateNode>(@class.Children.Last());
+            Assert.IsType<ViewComponentTagHelperIntermediateNode>(@class.Children.Last());
-            var tokenNode = vcthClass.Children[0] as IntermediateToken;
-            Assert.Equal(
-                @"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
-public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
-    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
-    {
-        _helper = helper;
-    }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.Int32 Foo { get; set; }
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
-        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var content = await _helper.InvokeAsync(""TagCloud"", new { Foo });
-        output.TagName = null;
-        output.Content.SetHtmlContent(content);
-    }
-}
-",
-                tokenNode.Content,
-                ignoreLineEndingDifferences: true);
-            Assert.Equal(TokenKind.CSharp, tokenNode.Kind);
         }
 
         [Fact]
@@ -165,33 +139,7 @@ public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.
             var @class = FindClassNode(irDocument);
             Assert.Equal(4, @class.Children.Count);
 
-            var vcthClass = Assert.IsType<CSharpCodeIntermediateNode>(@class.Children[3]);
+            Assert.IsType<ViewComponentTagHelperIntermediateNode>(@class.Children[3]);
-            var tokenNode = vcthClass.Children[0] as IntermediateToken;
-            Assert.Equal(
-                @"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
-public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
-    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
-    {
-        _helper = helper;
-    }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.Collections.Generic.Dictionary<System.String, System.Int32> Tags { get; set; }
-     = new System.Collections.Generic.Dictionary<System.String, System.Int32>();
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
-        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var content = await _helper.InvokeAsync(""TagCloud"", new { Tags });
-        output.TagName = null;
-        output.Content.SetHtmlContent(content);
-    }
-}
-",
-                tokenNode.Content,
-                ignoreLineEndingDifferences: true);
-            Assert.Equal(TokenKind.CSharp, tokenNode.Kind);
         }
 
         [Fact]
@@ -230,7 +178,7 @@ public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.
             };
 
             var irDocument = CreateIRDocument(engine, codeDocument);
-            
+
             var vcthFullName = "AspNetCore.test_cshtml.__Generated__TagCloudViewComponentTagHelper";
 
             // Act
@@ -249,32 +197,7 @@ public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.
             var @class = FindClassNode(irDocument);
             Assert.Equal(5, @class.Children.Count);
 
-            var vcthClass = Assert.IsType<CSharpCodeIntermediateNode>(@class.Children.Last());
+            Assert.IsType<ViewComponentTagHelperIntermediateNode>(@class.Children.Last());
-            var tokenNode = vcthClass.Children[0] as IntermediateToken;
-            Assert.Equal(
-                @"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
-public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
-    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
-    {
-        _helper = helper;
-    }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.Int32 Foo { get; set; }
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
-        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var content = await _helper.InvokeAsync(""TagCloud"", new { Foo });
-        output.TagName = null;
-        output.Content.SetHtmlContent(content);
-    }
-}
-",
-                tokenNode.Content,
-                ignoreLineEndingDifferences: true);
-            Assert.Equal(TokenKind.CSharp, tokenNode.Kind);
         }
 
         private RazorCodeDocument CreateDocument(string content)
@@ -329,21 +252,6 @@ public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.
             return visitor.Node;
         }
 
-        private string GetCSharpContent(IntermediateNode node)
-        {
-            var builder = new StringBuilder();
-            for (var i = 0; i < node.Children.Count; i++)
-            {
-                var child = node.Children[i] as IntermediateToken;
-                if (child.Kind == TokenKind.CSharp)
-                {
-                    builder.Append(child.Content);
-                }
-            }
-
-            return builder.ToString();
-        }
-
         private class ClassDeclarationNodeVisitor : IntermediateNodeWalker
         {
             public ClassDeclarationIntermediateNode Node { get; set; }

test/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X.Test/ViewComponentTagHelperTargetExtensionTest.cs

@@ -0,0 +1,120 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.Language.CodeGeneration;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Extensions.Version1_X
+{
+    public class ViewComponentTagHelperTargetExtensionTest
+    {
+        [Fact]
+        public void WriteViewComponentTagHelper_GeneratesViewComponentTagHelper()
+        {
+            // Arrange
+            var tagHelper = TagHelperDescriptorBuilder
+                .Create(ViewComponentTagHelperConventions.Kind, "TestTagHelper", "TestAssembly")
+                .TypeName("__Generated__TagCloudViewComponentTagHelper")
+                .BoundAttributeDescriptor(attribute => attribute
+                    .Name("Foo")
+                    .TypeName("System.Int32")
+                    .PropertyName("Foo"))
+                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("tagcloud"))
+                .AddMetadata(ViewComponentTagHelperMetadata.Name, "TagCloud")
+                .Build();
+
+            var extension = new ViewComponentTagHelperTargetExtension();
+            var context = TestCodeRenderingContext.CreateRuntime();
+            var node = new ViewComponentTagHelperIntermediateNode()
+            {
+                ClassName = "__Generated__TagCloudViewComponentTagHelper",
+                TagHelper = tagHelper
+            };
+
+            // Act
+            extension.WriteViewComponentTagHelper(context, node);
+
+            // Assert
+            var csharp = context.CodeWriter.GenerateCode();
+            Assert.Equal(
+                @"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
+public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
+{
+    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
+    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
+    {
+        _helper = helper;
+    }
+    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
+    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
+    public System.Int32 Foo { get; set; }
+    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
+    {
+        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
+        var content = await _helper.InvokeAsync(""TagCloud"", new { Foo });
+        output.TagName = null;
+        output.Content.SetHtmlContent(content);
+    }
+}
+",
+                csharp,
+                ignoreLineEndingDifferences: true);
+        }
+
+        [Fact]
+        public void WriteViewComponentTagHelper_GeneratesViewComponentTagHelper_WithIndexer()
+        {
+            // Arrange
+            var tagHelper = TagHelperDescriptorBuilder
+                .Create(ViewComponentTagHelperConventions.Kind, "TestTagHelper", "TestAssembly")
+                .TypeName("__Generated__TagCloudViewComponentTagHelper")
+                .BoundAttributeDescriptor(attribute => attribute
+                    .Name("Foo")
+                    .TypeName("System.Collections.Generic.Dictionary<System.String, System.Int32>")
+                    .PropertyName("Tags")
+                    .AsDictionaryAttribute("foo-", "System.Int32"))
+                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("tagcloud"))
+                .AddMetadata(ViewComponentTagHelperMetadata.Name, "TagCloud")
+                .Build();
+
+            var extension = new ViewComponentTagHelperTargetExtension();
+            var context = TestCodeRenderingContext.CreateRuntime();
+            var node = new ViewComponentTagHelperIntermediateNode()
+            {
+                ClassName = "__Generated__TagCloudViewComponentTagHelper",
+                TagHelper = tagHelper
+            };
+
+            // Act
+            extension.WriteViewComponentTagHelper(context, node);
+
+            // Assert
+            var csharp = context.CodeWriter.GenerateCode();
+            Assert.Equal(
+                @"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
+public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
+{
+    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
+    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
+    {
+        _helper = helper;
+    }
+    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
+    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
+    public System.Collections.Generic.Dictionary<System.String, System.Int32> Tags { get; set; }
+     = new System.Collections.Generic.Dictionary<System.String, System.Int32>();
+    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
+    {
+        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
+        var content = await _helper.InvokeAsync(""TagCloud"", new { Tags });
+        output.TagName = null;
+        output.Content.SetHtmlContent(content);
+    }
+}
+",
+                csharp,
+                ignoreLineEndingDifferences: true);
+        }
+    }
+}