Add ValidationSummaryTagHelper.

- Tested ValidationSummaryTagHelper behavior.
- Updated sample to utilize new ValidationSummaryTagHelper format.

#1251

samples/TagHelperSample.Web/Views/Home/Create.cshtml

@@ -10,13 +10,13 @@
     <div class="form-horizontal">
         @* validation summary tag helper will target just <div/> elements and append the list of errors *@
         @* - i.e. this helper, like <select/> helper has ContentBehavior.Append *@
-        @* validation-model-errors-only="true" implies validation-summary="true" *@
-        @* helper does nothing if model is valid and (client-side validation is disabled or validation-model-errors-only="true") *@
+        @* helper does nothing if model is valid and (client-side validation is disabled or validation-summary="ModelOnly") *@
         @* don't need a bound attribute to match Html.ValidationSummary()'s headerTag parameter; users wrap message as they wish *@
         @* initially at least, will not remove the <div/> if list isn't generated *@
         @* - should helper remove the <div/> if list isn't generated? *@
         @* - (Html.ValidationSummary returns empty string despite non-empty message parameter) *@
-        <div validation-summary="true" validation-model-errors-only="true">
+        @* Acceptable values are: "None", "ModelOnly" and "All" *@
+        <div validation-summary="ModelOnly">
             <span style="color:red">This is my message</span>
         </div>
 

samples/TagHelperSample.Web/Views/Home/Edit.cshtml

@@ -6,7 +6,7 @@
 
 <form>
     <div class="form-horizontal">
-        <div validation-summary="true"/>
+        <div validation-summary="All"/>
         <input type="hidden" for="Id" />
 
         <div class="form-group">

src/Microsoft.AspNet.Mvc.TagHelpers/Properties/AssemblyInfo.cs

@@ -0,0 +1,6 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Microsoft.AspNet.Mvc.TagHelpers.Test")]

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

@@ -58,6 +58,22 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
             return string.Format(CultureInfo.CurrentCulture, GetString("FormTagHelper_CannotDetermineAction"), p0, p1, p2, p3);
         }
 
+        /// <summary>
+        /// Cannot parse '{1}' value '{2}' for {0}. Acceptable values are '{3}', '{4}' and '{5}'.
+        /// </summary>
+        internal static string ValidationSummaryTagHelper_InvalidValidationSummaryValue
+        {
+            get { return GetString("ValidationSummaryTagHelper_InvalidValidationSummaryValue"); }
+        }
+
+        /// <summary>
+        /// Cannot parse '{1}' value '{2}' for {0}. Acceptable values are '{3}', '{4}' and '{5}'.
+        /// </summary>
+        internal static string FormatValidationSummaryTagHelper_InvalidValidationSummaryValue(object p0, object p1, object p2, object p3, object p4, object p5)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("ValidationSummaryTagHelper_InvalidValidationSummaryValue"), p0, p1, p2, p3, p4, p5);
+        }
+
         private static string GetString(string name, params string[] formatterNames)
         {
             var value = _resourceManager.GetString(name);

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

@@ -126,4 +126,7 @@
   <data name="FormTagHelper_CannotDetermineAction" xml:space="preserve">
     <value>Cannot determine an {1} for {0}. A {0} with a URL-based {1} must not have attributes starting with {3} or a {2} attribute.</value>
   </data>
+  <data name="ValidationSummaryTagHelper_InvalidValidationSummaryValue" xml:space="preserve">
+    <value>Cannot parse '{1}' value '{2}' for {0}. Acceptable values are '{3}', '{4}' and '{5}'.</value>
+  </data>
 </root>

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

@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNet.Mvc.TagHelpers
+{
+    /// <summary>
+    /// Acceptable validation summary rendering modes.
+    /// </summary>
+    public enum ValidationSummary
+    {
+        /// <summary>
+        /// No validation summary.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Validation summary with model-level errors only (excludes all property errors).
+        /// </summary>
+        ModelOnly,
+
+        /// <summary>
+        /// Validation summary with all errors.
+        /// </summary>
+        All
+    }
+}

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

@@ -0,0 +1,74 @@
+// Copyright (c) Microsoft Open Technologies, Inc. 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.AspNet.Mvc.Rendering;
+using Microsoft.AspNet.Razor.Runtime.TagHelpers;
+using Microsoft.AspNet.Razor.TagHelpers;
+
+namespace Microsoft.AspNet.Mvc.TagHelpers
+{
+    /// <summary>
+    /// <see cref="ITagHelper"/> implementation targeting &lt;div&gt; elements with a <c>validation-summary</c> 
+    /// attribute.
+    /// </summary>
+    [TagName("div")]
+    [ContentBehavior(ContentBehavior.Append)]
+    public class ValidationSummaryTagHelper : TagHelper
+    {
+        // Protected to ensure subclasses are correctly activated. Internal for ease of use when testing.
+        [Activate]
+        protected internal ViewContext ViewContext { get; set; }
+
+        // Protected to ensure subclasses are correctly activated. Internal for ease of use when testing.
+        [Activate]
+        protected internal IHtmlGenerator Generator { get; set; }
+
+        // TODO: Change to ValidationSummary enum once https://github.com/aspnet/Razor/issues/196 has been completed.
+        /// <summary>
+        /// If <c>All</c> or <c>ModelOnly</c>, appends a validation summary. Acceptable values are defined by the 
+        /// <see cref="ValidationSummary"/> enum.
+        /// </summary>
+        [HtmlAttributeName("validation-summary")]
+        public string ValidationSummaryValue { get; set; }
+
+        /// <inheritdoc />
+        /// Does nothing if <see cref="ValidationSummaryValue"/> is <c>null</c>, empty or "None".
+        public override void Process(TagHelperContext context, TagHelperOutput output)
+        {
+            if (!string.IsNullOrEmpty(ValidationSummaryValue))
+            {
+                ValidationSummary validationSummaryValue;
+                if (!Enum.TryParse(ValidationSummaryValue, ignoreCase: true, result: out validationSummaryValue))
+                {
+                    throw new InvalidOperationException(
+                        Resources.FormatValidationSummaryTagHelper_InvalidValidationSummaryValue(
+                            "<div>",
+                            "validation-summary",
+                            ValidationSummaryValue,
+                            ValidationSummary.All,
+                            ValidationSummary.ModelOnly,
+                            ValidationSummary.None));
+                }
+                else if (validationSummaryValue == ValidationSummary.None)
+                {
+                    return;
+                }
+
+                var validationModelErrorsOnly = validationSummaryValue == ValidationSummary.ModelOnly;
+                var tagBuilder = Generator.GenerateValidationSummary(
+                    ViewContext,
+                    excludePropertyErrors: validationModelErrorsOnly,
+                    message: null,
+                    headerTag: null,
+                    htmlAttributes: null);
+
+                if (tagBuilder != null)
+                {
+                    output.MergeAttributes(tagBuilder);
+                    output.Content += tagBuilder.InnerHtml;
+                }
+            }
+        }
+    }
+}

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

@@ -0,0 +1,289 @@
+// Copyright (c) Microsoft Open Technologies, Inc. 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.IO;
+using System.Reflection;
+using System.Threading.Tasks;
+using Microsoft.AspNet.Http;
+using Microsoft.AspNet.Mvc.ModelBinding;
+using Microsoft.AspNet.Mvc.Razor;
+using Microsoft.AspNet.Mvc.Rendering;
+using Microsoft.AspNet.PipelineCore;
+using Microsoft.AspNet.Razor.Runtime.TagHelpers;
+using Microsoft.AspNet.Routing;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNet.Mvc.TagHelpers
+{
+    public class ValidationSummaryTagHelperTest
+    {
+        [Fact]
+        public async Task ProcessAsync_GeneratesExpectedOutput()
+        {
+            // Arrange
+            var metadataProvider = new DataAnnotationsModelMetadataProvider();
+            var validationSummaryTagHelper = new ValidationSummaryTagHelper
+            {
+                ValidationSummaryValue = "All"
+            };
+
+            var tagHelperContext = new TagHelperContext(new Dictionary<string, object>());
+            var output = new TagHelperOutput(
+                "div",
+                attributes: new Dictionary<string, string>
+                {
+                    { "class", "form-control" }
+                },
+                content: "Custom Content");
+
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            Model model = null;
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            validationSummaryTagHelper.ViewContext = viewContext;
+            validationSummaryTagHelper.Generator = htmlGenerator;
+
+            // Act
+            await validationSummaryTagHelper.ProcessAsync(tagHelperContext, output);
+
+            // Assert
+            Assert.Equal(2, output.Attributes.Count);
+            var attribute = Assert.Single(output.Attributes, kvp => kvp.Key.Equals("class"));
+            Assert.Equal("form-control validation-summary-valid", attribute.Value);
+            attribute = Assert.Single(output.Attributes, kvp => kvp.Key.Equals("data-valmsg-summary"));
+            Assert.Equal("true", attribute.Value);
+            Assert.Equal("Custom Content<ul><li style=\"display:none\"></li>" + Environment.NewLine + "</ul>",
+                         output.Content);
+            Assert.Equal("div", output.TagName);
+        }
+
+        [Fact]
+        public async Task ProcessAsync_CallsIntoGenerateValidationSummaryWithExpectedParameters()
+        {
+            // Arrange
+            var validationSummaryTagHelper = new ValidationSummaryTagHelper
+            {
+                ValidationSummaryValue = "ModelOnly",
+            };
+            var output = new TagHelperOutput(
+                "div",
+                attributes: new Dictionary<string, string>(),
+                content: "Content of validation summary");
+            var expectedViewContext = CreateViewContext();
+            var generator = new Mock<IHtmlGenerator>();
+            generator
+                .Setup(mock => mock.GenerateValidationSummary(expectedViewContext, true, null, null, null))
+                .Returns(new TagBuilder("div"))
+                .Verifiable();
+            validationSummaryTagHelper.ViewContext = expectedViewContext;
+            validationSummaryTagHelper.Generator = generator.Object;
+
+            // Act & Assert
+            await validationSummaryTagHelper.ProcessAsync(context: null, output: output);
+
+            generator.Verify();
+            Assert.Equal("div", output.TagName);
+            Assert.Empty(output.Attributes);
+            Assert.Equal("Content of validation summary", output.Content);
+        }
+
+        [Fact]
+        public async Task ProcessAsync_MergesTagBuilderFromGenerateValidationSummary()
+        {
+            // Arrange
+            var validationSummaryTagHelper = new ValidationSummaryTagHelper
+            {
+                ValidationSummaryValue = "ModelOnly"
+            };
+            var output = new TagHelperOutput(
+                "div",
+                attributes: new Dictionary<string, string>(),
+                content: "Content of validation summary");
+            var tagBuilder = new TagBuilder("span2")
+            {
+                InnerHtml = "New HTML"
+            };
+
+            tagBuilder.Attributes.Add("data-foo", "bar");
+            tagBuilder.Attributes.Add("data-hello", "world");
+            tagBuilder.Attributes.Add("anything", "something");
+
+            var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
+            generator
+                .Setup(mock => mock.GenerateValidationSummary(
+                    It.IsAny<ViewContext>(),
+                    It.IsAny<bool>(),
+                    It.IsAny<string>(),
+                    It.IsAny<string>(),
+                    It.IsAny<object>()))
+                .Returns(tagBuilder);
+            var viewContext = CreateViewContext();
+            validationSummaryTagHelper.ViewContext = viewContext;
+            validationSummaryTagHelper.Generator = generator.Object;
+
+            // Act
+            await validationSummaryTagHelper.ProcessAsync(context: null, output: output);
+
+            // Assert
+            Assert.Equal(output.TagName, "div");
+            Assert.Equal(3, output.Attributes.Count);
+            var attribute = Assert.Single(output.Attributes, kvp => kvp.Key.Equals("data-foo"));
+            Assert.Equal("bar", attribute.Value);
+            attribute = Assert.Single(output.Attributes, kvp => kvp.Key.Equals("data-hello"));
+            Assert.Equal("world", attribute.Value);
+            attribute = Assert.Single(output.Attributes, kvp => kvp.Key.Equals("anything"));
+            Assert.Equal("something", attribute.Value);
+            Assert.Equal("Content of validation summaryNew HTML", output.Content);
+        }
+
+        [Theory]
+        [InlineData("")]
+        [InlineData(null)]
+        public async Task ProcessAsync_DoesNothingIfNullOrEmptyValidationSummaryValue(string validationSummaryValue)
+        {
+            // Arrange
+            var validationSummaryTagHelper = new ValidationSummaryTagHelper
+            {
+                ValidationSummaryValue = validationSummaryValue
+            };
+            var output = new TagHelperOutput(
+                "div",
+                attributes: new Dictionary<string, string>(),
+                content: "Content of validation message");
+
+            var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
+            var viewContext = CreateViewContext();
+            validationSummaryTagHelper.ViewContext = viewContext;
+            validationSummaryTagHelper.Generator = generator.Object;
+
+            // Act
+            await validationSummaryTagHelper.ProcessAsync(context: null, output: output);
+
+            // Assert
+            Assert.Equal("div", output.TagName);
+            Assert.Empty(output.Attributes);
+            Assert.Equal("Content of validation message", output.Content);
+        }
+
+        [Theory]
+        [InlineData("All")]
+        [InlineData("all")]
+        [InlineData("ModelOnly")]
+        [InlineData("modelonly")]
+        public async Task ProcessAsync_GeneratesValidationSummaryWhenNotNone_IgnoresCase(string validationSummary)
+        {
+            // Arrange
+            var validationSummaryTagHelper = new ValidationSummaryTagHelper
+            {
+                ValidationSummaryValue = validationSummary
+            };
+            var output = new TagHelperOutput(
+                "div",
+                attributes: new Dictionary<string, string>(),
+                content: "Content of validation message");
+            var tagBuilder = new TagBuilder("span2")
+            {
+                InnerHtml = "New HTML"
+            };
+
+            var generator = new Mock<IHtmlGenerator>();
+            generator
+                .Setup(mock => mock.GenerateValidationSummary(
+                    It.IsAny<ViewContext>(),
+                    It.IsAny<bool>(),
+                    It.IsAny<string>(),
+                    It.IsAny<string>(),
+                    It.IsAny<object>()))
+                .Returns(tagBuilder)
+                .Verifiable();
+            var viewContext = CreateViewContext();
+            validationSummaryTagHelper.ViewContext = viewContext;
+            validationSummaryTagHelper.Generator = generator.Object;
+
+            // Act
+            await validationSummaryTagHelper.ProcessAsync(context: null, output: output);
+
+            // Assert
+            Assert.Equal("div", output.TagName);
+            Assert.Empty(output.Attributes);
+            Assert.Equal("Content of validation messageNew HTML", output.Content);
+            generator.Verify();
+        }
+
+        [Theory]
+        [InlineData("None")]
+        [InlineData("none")]
+        public async Task ProcessAsync_DoesNotGenerateValidationSummaryWhenNone_IgnoresCase(string validationSummary)
+        {
+            // Arrange
+            var validationSummaryTagHelper = new ValidationSummaryTagHelper
+            {
+                ValidationSummaryValue = validationSummary
+            };
+            var output = new TagHelperOutput(
+                "div",
+                attributes: new Dictionary<string, string>(),
+                content: "Content of validation message");
+            var tagBuilder = new TagBuilder("span2")
+            {
+                InnerHtml = "New HTML"
+            };
+
+            var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
+
+            // Act
+            await validationSummaryTagHelper.ProcessAsync(context: null, output: output);
+
+            // Assert
+            Assert.Equal("div", output.TagName);
+            Assert.Empty(output.Attributes);
+            Assert.Equal("Content of validation message", output.Content);
+        }
+
+        [Fact]
+        public async Task ProcessAsync_ThrowsWhenInvalidValidationSummaryValue()
+        {
+            // Arrange
+            var validationSummaryTagHelper = new ValidationSummaryTagHelper
+            {
+                ValidationSummaryValue = "Hello World"
+            };
+            var output = new TagHelperOutput(
+                "div",
+                attributes: new Dictionary<string, string>(),
+                content: "Content of validation message");
+            var expectedViewContext = CreateViewContext();
+            var expectedMessage = "Cannot parse 'validation-summary' value 'Hello World' for <div>. Acceptable values " +
+                                  "are 'All', 'ModelOnly' and 'None'.";
+
+            // Act
+            var ex = await Assert.ThrowsAsync<InvalidOperationException>(() => 
+                validationSummaryTagHelper.ProcessAsync(context: null, output: output));
+
+            // Assert
+            Assert.Equal(expectedMessage, ex.Message);
+        }
+
+        private static ViewContext CreateViewContext()
+        {
+            var actionContext = new ActionContext(
+                new DefaultHttpContext(),
+                new RouteData(),
+                new ActionDescriptor());
+
+            return new ViewContext(
+                actionContext,
+                Mock.Of<IView>(),
+                new ViewDataDictionary(
+                    new EmptyModelMetadataProvider()),
+                TextWriter.Null);
+        }
+
+        private class Model
+        {
+            public string Text { get; set; }
+        }
+    }
+}