TagHelpers attribute targeting - part 1

src/Microsoft.AspNet.Mvc.TagHelpers/InputTagHelper.cs

@@ -15,6 +15,7 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
     /// <summary>
     /// <see cref="ITagHelper"/> implementation targeting &lt;input&gt; elements with an <c>asp-for</c> attribute.
     /// </summary>
+    [TargetElement("input", Attributes = ForAttributeName)]
     public class InputTagHelper : TagHelper
     {
         private const string ForAttributeName = "asp-for";
@@ -121,93 +122,79 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
                 output.CopyHtmlAttribute(nameof(Value), context);
             }
 
-            if (For == null)
+            // Note null or empty For.Name is allowed because TemplateInfo.HtmlFieldPrefix may be sufficient.
+            // IHtmlGenerator will enforce name requirements.
+            var metadata = For.Metadata;
+            var modelExplorer = For.ModelExplorer;
+            if (metadata == null)
             {
-                // Regular HTML <input/> element. Just make sure Format wasn't specified.
+                throw new InvalidOperationException(Resources.FormatTagHelpers_NoProvidedMetadata(
-                if (Format != null)
+                    "<input>",
-                {
+                    ForAttributeName,
-                    throw new InvalidOperationException(Resources.FormatInputTagHelper_UnableToFormat(
+                    nameof(IModelMetadataProvider),
-                        "<input>",
+                    For.Name));
-                        ForAttributeName,
+            }
-                        FormatAttributeName));
+
-                }
+            string inputType;
+            string inputTypeHint;
+            if (string.IsNullOrEmpty(InputTypeName))
+            {
+                // Note GetInputType never returns null.
+                inputType = GetInputType(modelExplorer, out inputTypeHint);
             }
             else
             {
-                // Note null or empty For.Name is allowed because TemplateInfo.HtmlFieldPrefix may be sufficient.
+                inputType = InputTypeName.ToLowerInvariant();
-                // IHtmlGenerator will enforce name requirements.
+                inputTypeHint = null;
-                var metadata = For.Metadata;
+            }
-                var modelExplorer = For.ModelExplorer;
-                if (metadata == null)
-                {
-                    throw new InvalidOperationException(Resources.FormatTagHelpers_NoProvidedMetadata(
-                        "<input>",
-                        ForAttributeName,
-                        nameof(IModelMetadataProvider),
-                        For.Name));
-                }
 
-                string inputType;
+            // inputType may be more specific than default the generator chooses below.
-                string inputTypeHint;
+            if (!output.Attributes.ContainsKey("type"))
-                if (string.IsNullOrEmpty(InputTypeName))
+            {
-                {
+                output.Attributes["type"] = inputType;
-                    // Note GetInputType never returns null.
+            }
-                    inputType = GetInputType(modelExplorer, out inputTypeHint);
-                }
-                else
-                {
-                    inputType = InputTypeName.ToLowerInvariant();
-                    inputTypeHint = null;
-                }
 
-                // inputType may be more specific than default the generator chooses below.
+            TagBuilder tagBuilder;
-                if (!output.Attributes.ContainsKey("type"))
+            switch (inputType)
-                {
+            {
-                    output.Attributes["type"] = inputType;
+                case "checkbox":
-                }
+                    GenerateCheckBox(modelExplorer, output);
+                    return;
 
-                TagBuilder tagBuilder;
+                case "hidden":
-                switch (inputType)
+                    tagBuilder = Generator.GenerateHidden(
-                {
+                        ViewContext,
-                    case "checkbox":
+                        modelExplorer,
-                        GenerateCheckBox(modelExplorer, output);
+                        For.Name,
-                        return;
+                        value: For.Model,
+                        useViewData: false,
+                        htmlAttributes: null);
+                    break;
 
-                    case "hidden":
+                case "password":
-                        tagBuilder = Generator.GenerateHidden(
+                    tagBuilder = Generator.GeneratePassword(
-                            ViewContext,
+                        ViewContext,
-                            modelExplorer,
+                        modelExplorer,
-                            For.Name,
+                        For.Name,
-                            value: For.Model,
+                        value: null,
-                            useViewData: false,
+                        htmlAttributes: null);
-                            htmlAttributes: null);
+                    break;
-                        break;
 
-                    case "password":
+                case "radio":
-                        tagBuilder = Generator.GeneratePassword(
+                    tagBuilder = GenerateRadio(modelExplorer);
-                            ViewContext,
+                    break;
-                            modelExplorer,
-                            For.Name,
-                            value: null,
-                            htmlAttributes: null);
-                        break;
 
-                    case "radio":
+                default:
-                        tagBuilder = GenerateRadio(modelExplorer);
+                    tagBuilder = GenerateTextBox(modelExplorer, inputTypeHint, inputType);
-                        break;
+                    break;
+            }
 
-                    default:
+            if (tagBuilder != null)
-                        tagBuilder = GenerateTextBox(modelExplorer, inputTypeHint, inputType);
+            {
-                        break;
+                // This TagBuilder contains the one <input/> element of interest. Since this is not the "checkbox"
-                }
+                // special-case, output is a self-closing element no longer guarunteed.
-
+                output.MergeAttributes(tagBuilder);
-                if (tagBuilder != null)
+                output.Content.Append(tagBuilder.InnerHtml);
-                {
-                    // This TagBuilder contains the one <input/> element of interest. Since this is not the "checkbox"
-                    // special-case, output is a self-closing element no longer guarunteed.
-                    output.MergeAttributes(tagBuilder);
-                    output.Content.Append(tagBuilder.InnerHtml);
-                }
             }
         }
 

src/Microsoft.AspNet.Mvc.TagHelpers/LabelTagHelper.cs

@@ -10,6 +10,7 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
     /// <summary>
     /// <see cref="ITagHelper"/> implementation targeting &lt;label&gt; elements with an <c>asp-for</c> attribute.
     /// </summary>
+    [TargetElement("label", Attributes = ForAttributeName)]
     public class LabelTagHelper : TagHelper
     {
         private const string ForAttributeName = "asp-for";
@@ -32,34 +33,32 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
         /// <remarks>Does nothing if <see cref="For"/> is <c>null</c>.</remarks>
         public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
         {
-            if (For != null)
+            var tagBuilder = Generator.GenerateLabel(
+                ViewContext,
+                For.ModelExplorer,
+                For.Name,
+                labelText: null,
+                htmlAttributes: null);
+
+            if (tagBuilder != null)
             {
-                var tagBuilder = Generator.GenerateLabel(ViewContext,
+                output.MergeAttributes(tagBuilder);
-                                                         For.ModelExplorer,
-                                                         For.Name,
-                                                         labelText: null,
-                                                         htmlAttributes: null);
 
-                if (tagBuilder != null)
+                // We check for whitespace to detect scenarios such as:
+                // <label for="Name">
+                // </label>
+                if (!output.IsContentModified)
                 {
-                    output.MergeAttributes(tagBuilder);
+                    var childContent = await context.GetChildContentAsync();
 
-                    // We check for whitespace to detect scenarios such as:
+                    if (childContent.IsWhiteSpace)
-                    // <label for="Name">
-                    // </label>
-                    if (!output.IsContentModified)
                     {
-                        var childContent = await context.GetChildContentAsync();
+                        // Provide default label text since there was nothing useful in the Razor source.
-
+                        output.Content.SetContent(tagBuilder.InnerHtml);
-                        if (childContent.IsWhiteSpace)
+                    }
-                        {
+                    else
-                            // Provide default label text since there was nothing useful in the Razor source.
+                    {
-                            output.Content.SetContent(tagBuilder.InnerHtml);
+                        output.Content.SetContent(childContent);
-                        }
-                        else
-                        {
-                            output.Content.SetContent(childContent);
-                        }
                     }
                 }
             }

src/Microsoft.AspNet.Mvc.TagHelpers/Properties/Resources.Designer.cs

@@ -74,22 +74,6 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
             return string.Format(CultureInfo.CurrentCulture, GetString("InputTagHelper_InvalidExpressionResult"), p0, p1, p2, p3, p4, p5);
         }
 
-        /// <summary>
-        /// Unable to format without a '{1}' expression for {0}. '{2}' must be null if '{1}' is null.
-        /// </summary>
-        internal static string InputTagHelper_UnableToFormat
-        {
-            get { return GetString("InputTagHelper_UnableToFormat"); }
-        }
-
-        /// <summary>
-        /// Unable to format without a '{1}' expression for {0}. '{2}' must be null if '{1}' is null.
-        /// </summary>
-        internal static string FormatInputTagHelper_UnableToFormat(object p0, object p1, object p2)
-        {
-            return string.Format(CultureInfo.CurrentCulture, GetString("InputTagHelper_UnableToFormat"), p0, p1, p2);
-        }
-
         /// <summary>
         /// '{1}' must not be null for {0} if '{2}' is '{3}'.
         /// </summary>

src/Microsoft.AspNet.Mvc.TagHelpers/Resources.resx

@@ -129,9 +129,6 @@
   <data name="InputTagHelper_InvalidExpressionResult" xml:space="preserve">
     <value>Unexpected '{1}' expression result type '{2}' for {0}. '{1}' must be of type '{3}' if '{4}' is '{5}'.</value>
   </data>
-  <data name="InputTagHelper_UnableToFormat" xml:space="preserve">
-    <value>Unable to format without a '{1}' expression for {0}. '{2}' must be null if '{1}' is null.</value>
-  </data>
   <data name="InputTagHelper_ValueRequired" xml:space="preserve">
     <value>'{1}' must not be null for {0} if '{2}' is '{3}'.</value>
   </data>

src/Microsoft.AspNet.Mvc.TagHelpers/ValidationMessageTagHelper.cs

@@ -8,10 +8,10 @@ using Microsoft.AspNet.Razor.Runtime.TagHelpers;
 namespace Microsoft.AspNet.Mvc.TagHelpers
 {
     /// <summary>
-    /// <see cref="ITagHelper"/> implementation targeting &lt;span&gt; elements with an <c>asp-validation-for</c>
+    /// <see cref="ITagHelper"/> implementation targeting any HTML element with an <c>asp-validation-for</c>
     /// attribute.
     /// </summary>
-    [TargetElement("span")]
+    [TargetElement("span", Attributes = ValidationForAttributeName)]
     public class ValidationMessageTagHelper : TagHelper
     {
         private const string ValidationForAttributeName = "asp-validation-for";

src/Microsoft.AspNet.Mvc.TagHelpers/ValidationSummaryTagHelper.cs

@@ -8,10 +8,10 @@ using Microsoft.AspNet.Razor.Runtime.TagHelpers;
 namespace Microsoft.AspNet.Mvc.TagHelpers
 {
     /// <summary>
-    /// <see cref="ITagHelper"/> implementation targeting &lt;div&gt; elements with an <c>asp-validation-summary</c>
+    /// <see cref="ITagHelper"/> implementation targeting any HTML element with an <c>asp-validation-summary</c>
     /// attribute.
     /// </summary>
-    [TargetElement("div")]
+    [TargetElement("div", Attributes = ValidationSummaryAttributeName)]
     public class ValidationSummaryTagHelper : TagHelper
     {
         private const string ValidationSummaryAttributeName = "asp-validation-summary";

test/Microsoft.AspNet.Mvc.FunctionalTests/Compiler/Resources/TagHelpersWebSite.Employee.Create.Invalid.html

@@ -69,7 +69,7 @@
 
             <div class="form-group">
                 <div class="col-md-offset-2 col-md-10">
-                    <input class="btn btn-default" type="submit" value="Create" />
+                    <input type="submit" value="Create" class="btn btn-default" />
                 </div>
             </div>
         </div>

test/Microsoft.AspNet.Mvc.FunctionalTests/Compiler/Resources/TagHelpersWebSite.Employee.Create.html

@@ -67,7 +67,7 @@
 
             <div class="form-group">
                 <div class="col-md-offset-2 col-md-10">
-                    <input class="btn btn-default" type="submit" value="Create" />
+                    <input type="submit" value="Create" class="btn btn-default" />
                 </div>
             </div>
         </div>

test/Microsoft.AspNet.Mvc.TagHelpers.Test/InputTagHelperTest.cs

@@ -617,62 +617,6 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
             Assert.Equal(expectedTagName, output.TagName);
         }
 
-        [Fact]
-        public async Task TagHelper_RestoresTypeAndValue_IfForNotBound()
-        {
-            // Arrange
-            var expectedAttributes = new Dictionary<string, string>
-            {
-                { "class", "form-control" },
-                { "type", "datetime" },
-                { "value", "2014-10-15T23:24:19.000-7:00" },
-            };
-            var expectedPreContent = "original pre-content";
-            var expectedContent = "original content";
-            var expectedPostContent = "original post-content";
-            var expectedTagName = "input";
-
-            var tagHelperContext = new TagHelperContext(
-                allAttributes: new Dictionary<string, object>(),
-                items: new Dictionary<object, object>(),
-                uniqueId: "test",
-                getChildContentAsync: () =>
-                {
-                    var tagHelperContent = new DefaultTagHelperContent();
-                    tagHelperContent.SetContent("Something");
-                    return Task.FromResult<TagHelperContent>(tagHelperContent);
-                });
-
-            var output = new TagHelperOutput(expectedTagName, expectedAttributes)
-            {
-                SelfClosing = false,
-            };
-            output.PreContent.SetContent(expectedPreContent);
-            output.Content.SetContent(expectedContent);
-            output.PostContent.SetContent(expectedPostContent);
-
-            var htmlGenerator = new TestableHtmlGenerator(new EmptyModelMetadataProvider())
-            {
-                ValidationAttributes =
-                {
-                    {  "valid", "from validation attributes" },
-                }
-            };
-            var tagHelper = GetTagHelper(htmlGenerator, model: null, propertyName: nameof(Model.Text));
-            tagHelper.For = null;
-
-            // Act
-            await tagHelper.ProcessAsync(tagHelperContext, output);
-
-            // Assert
-            Assert.Equal(expectedAttributes, output.Attributes);
-            Assert.Equal(expectedPreContent, output.PreContent.GetContent());
-            Assert.Equal(expectedContent, output.Content.GetContent());
-            Assert.Equal(expectedPostContent, output.PostContent.GetContent());
-            Assert.False(output.SelfClosing);
-            Assert.Equal(expectedTagName, output.TagName);
-        }
-
         private static InputTagHelper GetTagHelper(
             IHtmlGenerator htmlGenerator, 
             object model, 
@@ -689,38 +633,6 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
                 metadataProvider: metadataProvider);
         }
 
-        [Fact]
-        public async Task ProcessAsync_Throws_IfForNotBoundButFormatIs()
-        {
-            // Arrange
-            var contextAttributes = new Dictionary<string, object>();
-            var originalAttributes = new Dictionary<string, string>();
-            var expectedTagName = "select";
-            var expectedMessage = "Unable to format without a 'asp-for' expression for <input>. 'asp-format' must " +
-                "be null if 'asp-for' is null.";
-
-            var tagHelperContext = new TagHelperContext(
-                allAttributes: new Dictionary<string, object>(),
-                items: new Dictionary<object, object>(),
-                uniqueId: "test",
-                getChildContentAsync: () =>
-                {
-                    var tagHelperContent = new DefaultTagHelperContent();
-                    tagHelperContent.SetContent("Something");
-                    return Task.FromResult<TagHelperContent>(tagHelperContent);
-                });
-            var output = new TagHelperOutput(expectedTagName, originalAttributes);
-            var tagHelper = new InputTagHelper
-            {
-                Format = "{0}",
-            };
-
-            // Act & Assert
-            var exception = await Assert.ThrowsAsync<InvalidOperationException>(
-                () => tagHelper.ProcessAsync(tagHelperContext, output));
-            Assert.Equal(expectedMessage, exception.Message);
-        }
-
         private static InputTagHelper GetTagHelper(
             IHtmlGenerator htmlGenerator,
             object container,

test/Microsoft.AspNet.Mvc.TagHelpers.Test/LabelTagHelperTest.cs

@@ -228,59 +228,6 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
             Assert.Equal(expectedTagName, output.TagName);
         }
 
-        [Fact]
-        public async Task TagHelper_LeavesOutputUnchanged_IfForNotBound2()
-        {
-            // Arrange
-            var expectedAttributes = new Dictionary<string, string>
-            {
-                { "class", "form-control" },
-            };
-            var expectedPreContent = "original pre-content";
-            var expectedContent = "original content";
-            var expectedPostContent = "original post-content";
-            var expectedTagName = "label";
-
-            var metadataProvider = new TestModelMetadataProvider();
-            var modelExplorer = metadataProvider
-                .GetModelExplorerForType(typeof(Model), model: null)
-                .GetExplorerForProperty(nameof(Model.Text));
-            var modelExpression = new ModelExpression(nameof(Model.Text), modelExplorer);
-
-            var tagHelper = new LabelTagHelper();
-
-            var tagHelperContext = new TagHelperContext(
-                allAttributes: new Dictionary<string, object>(),
-                items: new Dictionary<object, object>(),
-                uniqueId: "test",
-                getChildContentAsync: () =>
-                {
-                    var tagHelperContent = new DefaultTagHelperContent();
-                    tagHelperContent.SetContent("Something");
-                    return Task.FromResult<TagHelperContent>(tagHelperContent);
-                });
-            var output = new TagHelperOutput(expectedTagName, expectedAttributes);
-            output.PreContent.SetContent(expectedPreContent);
-            output.Content.SetContent(expectedContent);
-            output.PostContent.SetContent(expectedPostContent);
-
-            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
-            Model model = null;
-            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
-            tagHelper.ViewContext = viewContext;
-            tagHelper.Generator = htmlGenerator;
-
-            // Act
-            await tagHelper.ProcessAsync(tagHelperContext, output);
-
-            // Assert
-            Assert.Equal(expectedAttributes, output.Attributes);
-            Assert.Equal(expectedPreContent, output.PreContent.GetContent());
-            Assert.Equal(expectedContent, output.Content.GetContent());
-            Assert.Equal(expectedPostContent, output.PostContent.GetContent());
-            Assert.Equal(expectedTagName, output.TagName);
-        }
-
         public class TagHelperOutputContent
         {
             public TagHelperOutputContent(string originalChildContent,