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Modify TagHelpers to use new content mode design. 

- React to aspnet/Razor#221
- Modified existing TagHelpers to no longer rely on ContentBehavior and to instead utilize GetChildContentAsync, PreContent, Content and PostContent.
This commit is contained in:
N. Taylor Mullen 2014-12-17 16:32:05 -08:00 committed by NTaylorMullen
parent 2cf56c7c83
commit 7b52559366
13 changed files with 64 additions and 41 deletions
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4
samples/TagHelperSample.Web/Views/Home/Create.cshtml
View File

@ -13,7 +13,7 @@
<form asp-anti-forgery="false" asp-action="Create">
<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 *@
@* - i.e. this helper, like <select/> helper appends content. *@
@* helper does nothing if model is valid and (client-side validation is disabled or
asp-validation-summary="ValidationSummary.ModelOnly") *@
@* don't need a bound attribute to match Html.ValidationSummary()'s headerTag parameter; users wrap message as they wish *@
@ -48,7 +48,7 @@
<div class="form-group">
<label asp-for="YearsEmployeed" class="control-label col-md-2" />
<div class="col-md-10">
@* <select/> tag helper has ContentBehavior.Append -- items render after static options *@
@* <select/> items render after static options *@
@{ var @object = "multiple"; }
<select asp-for="@(Model.YearsEmployeed)" asp-items="@((IEnumerable<SelectListItem>)ViewBag.Items)" size="2" class="form-control" multiple="@(@object)">
@* Static use of "selected" attribute may cause HTML errors if in a single-selection <select/> *@

14
src/Microsoft.AspNet.Mvc.Razor/RazorPage.cs
View File

@ -155,6 +155,18 @@ namespace Microsoft.AspNet.Mvc.Razor
/// be buffered until <see cref="EndWritingScope"/> is called.
/// </remarks>
public void StartWritingScope()
{
StartWritingScope(new StringWriter());
}
/// <summary>
/// Starts a new writing scope with the given <paramref name="writer"/>.
/// </summary>
/// <remarks>
/// All writes to the <see cref="Output"/> or <see cref="ViewContext.Writer"/> after calling this method will
/// be buffered until <see cref="EndWritingScope"/> is called.
/// </remarks>
public void StartWritingScope(TextWriter writer)
{
// If there isn't a base writer take the ViewContext.Writer
if (_originalWriter == null)
@ -164,7 +176,7 @@ namespace Microsoft.AspNet.Mvc.Razor
// We need to replace the ViewContext's Writer to ensure that all content (including content written
// from HTML helpers) is redirected.
ViewContext.Writer = new StringWriter();
ViewContext.Writer = writer;
_writerScopes.Push(ViewContext.Writer);
}

6
src/Microsoft.AspNet.Mvc.TagHelpers/FormTagHelper.cs
View File

@ -6,14 +6,12 @@ using System.Collections.Generic;
using System.Linq;
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;form&gt; elements.
/// </summary>
[ContentBehavior(ContentBehavior.Append)]
public class FormTagHelper : TagHelper
{
private const string ActionAttributeName = "asp-action";
@ -106,7 +104,7 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
if (tagBuilder != null)
{
output.MergeAttributes(tagBuilder);
output.Content += tagBuilder.InnerHtml;
output.PostContent += tagBuilder.InnerHtml;
output.SelfClosing = false;
}
}
@ -116,7 +114,7 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
var antiForgeryTagBuilder = Generator.GenerateAntiForgery(ViewContext);
if (antiForgeryTagBuilder != null)
{
output.Content += antiForgeryTagBuilder.ToString(TagRenderMode.SelfClosing);
output.PostContent += antiForgeryTagBuilder.ToString(TagRenderMode.SelfClosing);
}
}
}

1
src/Microsoft.AspNet.Mvc.TagHelpers/InputTagHelper.cs
View File

@ -15,7 +15,6 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
/// <summary>
/// <see cref="ITagHelper"/> implementation targeting &lt;input&gt; elements with an <c>asp-for</c> attribute.
/// </summary>
[ContentBehavior(ContentBehavior.Replace)]
public class InputTagHelper : TagHelper
{
private const string ForAttributeName = "asp-for";

19
src/Microsoft.AspNet.Mvc.TagHelpers/LabelTagHelper.cs
View File

@ -1,16 +1,15 @@
// 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.Threading.Tasks;
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;label&gt; elements with an <c>asp-for</c> attribute.
/// </summary>
[ContentBehavior(ContentBehavior.Modify)]
public class LabelTagHelper : TagHelper
{
private const string ForAttributeName = "asp-for";
@ -31,7 +30,7 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
/// <inheritdoc />
/// <remarks>Does nothing if <see cref="For"/> is <c>null</c>.</remarks>
public override void Process(TagHelperContext context, TagHelperOutput output)
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
if (For != null)
{
@ -48,9 +47,19 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
// We check for whitespace to detect scenarios such as:
// <label for="Name">
// </label>
if (string.IsNullOrWhiteSpace(output.Content))
if (!output.ContentSet)
{
output.Content = tagBuilder.InnerHtml;
var childContent = await context.GetChildContentAsync();
if (string.IsNullOrWhiteSpace(childContent))
{
// Provide default label text since there was nothing useful in the Razor source.
output.Content = tagBuilder.InnerHtml;
}
else
{
output.Content = childContent;
}
}
}
}

14
src/Microsoft.AspNet.Mvc.TagHelpers/OptionTagHelper.cs
View File

@ -3,6 +3,7 @@
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.AspNet.Mvc.Rendering;
using Microsoft.AspNet.Razor.Runtime.TagHelpers;
using Microsoft.AspNet.Razor.TagHelpers;
@ -13,11 +14,10 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
/// <see cref="ITagHelper"/> implementation targeting &lt;option&gt; elements.
/// </summary>
/// <remarks>
/// This <see cref="ITagHelper"/> works in conjunction with <see cref="SelectTagHelper"/>. It has
/// <see cref="ContentBehavior.Modify"/> in order to read element's content but does not modify that content. The
/// only modification it makes is to add a <c>selected</c> attribute in some cases.
/// This <see cref="ITagHelper"/> works in conjunction with <see cref="SelectTagHelper"/>. It reads elements
/// content but does not modify that content. The only modification it makes is to add a <c>selected</c> attribute
/// in some cases.
/// </remarks>
[ContentBehavior(ContentBehavior.Modify)]
public class OptionTagHelper : TagHelper
{
// Protected to ensure subclasses are correctly activated. Internal for ease of use when testing.
@ -51,7 +51,7 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
/// <see cref="ICollection{string}"/> instance. Also does nothing if the associated &lt;option&gt; is already
/// selected.
/// </remarks>
public override void Process(TagHelperContext context, TagHelperOutput output)
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
// Pass through attributes that are also well-known HTML attributes.
if (Value != null)
@ -84,9 +84,9 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
}
// Select this <option/> element if value attribute or content matches a selected value. Callers
// encode values as-needed before setting TagHelperOutput.Content. But TagHelperOutput itself
// encode values as-needed while executing child content. But TagHelperOutput itself
// encodes attribute values later, when GenerateStartTag() is called.
var text = output.Content;
var text = await context.GetChildContentAsync();
var selected = (Value != null) ? selectedValues.Contains(Value) : encodedValues.Contains(text);
if (selected)
{

3
src/Microsoft.AspNet.Mvc.TagHelpers/SelectTagHelper.cs
View File

@ -15,7 +15,6 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
/// <summary>
/// <see cref="ITagHelper"/> implementation targeting &lt;select&gt; elements with an <c>asp-for</c> attribute.
/// </summary>
[ContentBehavior(ContentBehavior.Append)]
public class SelectTagHelper : TagHelper
{
private const string ForAttributeName = "asp-for";
@ -146,7 +145,7 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
if (tagBuilder != null)
{
output.MergeAttributes(tagBuilder);
output.Content += tagBuilder.InnerHtml;
output.PostContent += tagBuilder.InnerHtml;
output.SelfClosing = false;
}

1
src/Microsoft.AspNet.Mvc.TagHelpers/TextAreaTagHelper.cs
View File

@ -10,7 +10,6 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
/// <summary>
/// <see cref="ITagHelper"/> implementation targeting &lt;textarea&gt; elements with an <c>asp-for</c> attribute.
/// </summary>
[ContentBehavior(ContentBehavior.Replace)]
[HtmlElementName("textarea")]
public class TextAreaTagHelper : TagHelper
{

19
src/Microsoft.AspNet.Mvc.TagHelpers/ValidationMessageTagHelper.cs
View File

@ -1,9 +1,9 @@
// 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.Threading.Tasks;
using Microsoft.AspNet.Mvc.Rendering;
using Microsoft.AspNet.Razor.Runtime.TagHelpers;
using Microsoft.AspNet.Razor.TagHelpers;
namespace Microsoft.AspNet.Mvc.TagHelpers
{
@ -12,7 +12,6 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
/// attribute.
/// </summary>
[HtmlElementName("span")]
[ContentBehavior(ContentBehavior.Modify)]
public class ValidationMessageTagHelper : TagHelper
{
private const string ValidationForAttributeName = "asp-validation-for";
@ -33,7 +32,7 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
/// <inheritdoc />
/// <remarks>Does nothing if <see cref="For"/> is <c>null</c>.</remarks>
public override void Process(TagHelperContext context, TagHelperOutput output)
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
if (For != null)
{
@ -50,9 +49,19 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
// We check for whitespace to detect scenarios such as:
// <span validation-for="Name">
// </span>
if (string.IsNullOrWhiteSpace(output.Content))
if (!output.ContentSet)
{
output.Content = tagBuilder.InnerHtml;
var childContent = await context.GetChildContentAsync();
if (string.IsNullOrWhiteSpace(childContent))
{
// Provide default label text since there was nothing useful in the Razor source.
output.Content = tagBuilder.InnerHtml;
}
else
{
output.Content = childContent;
}
}
}
}

3
src/Microsoft.AspNet.Mvc.TagHelpers/ValidationSummaryTagHelper.cs
View File

@ -13,7 +13,6 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
/// attribute.
/// </summary>
[HtmlElementName("div")]
[ContentBehavior(ContentBehavior.Append)]
public class ValidationSummaryTagHelper : TagHelper
{
private const string ValidationSummaryAttributeName = "asp-validation-summary";
@ -81,7 +80,7 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
if (tagBuilder != null)
{
output.MergeAttributes(tagBuilder);
output.Content += tagBuilder.InnerHtml;
output.PostContent += tagBuilder.InnerHtml;
}
}
}

9
test/WebSites/ActivatorWebSite/TagHelpers/HiddenTagHelper.cs
View File

@ -4,12 +4,11 @@
using Microsoft.AspNet.Mvc;
using Microsoft.AspNet.Mvc.Rendering;
using Microsoft.AspNet.Razor.Runtime.TagHelpers;
using Microsoft.AspNet.Razor.TagHelpers;
using System.Threading.Tasks;
namespace ActivatorWebSite.TagHelpers
{
[HtmlElementName("span")]
[ContentBehavior(ContentBehavior.Modify)]
public class HiddenTagHelper : TagHelper
{
public string Name { get; set; }
@ -17,9 +16,11 @@ namespace ActivatorWebSite.TagHelpers
[Activate]
public IHtmlHelper HtmlHelper { get; set; }
public override void Process(TagHelperContext context, TagHelperOutput output)
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
output.Content = HtmlHelper.Hidden(Name, output.Content).ToString();
var content = await context.GetChildContentAsync();
output.Content = HtmlHelper.Hidden(Name, content).ToString();
}
}
}

9
test/WebSites/ActivatorWebSite/TagHelpers/RepeatContentTagHelper.cs
View File

@ -4,12 +4,11 @@
using Microsoft.AspNet.Mvc;
using Microsoft.AspNet.Mvc.Rendering;
using Microsoft.AspNet.Razor.Runtime.TagHelpers;
using Microsoft.AspNet.Razor.TagHelpers;
using System.Threading.Tasks;
namespace ActivatorWebSite.TagHelpers
{
[HtmlElementName("div")]
[ContentBehavior(ContentBehavior.Modify)]
public class RepeatContentTagHelper : TagHelper
{
public int RepeatContent { get; set; }
@ -19,14 +18,14 @@ namespace ActivatorWebSite.TagHelpers
[Activate]
public IHtmlHelper HtmlHelper { get; set; }
public override void Process(TagHelperContext context, TagHelperOutput output)
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
var content = await context.GetChildContentAsync();
var repeatContent = HtmlHelper.Encode(Expression.Metadata.Model.ToString());
if (string.IsNullOrEmpty(repeatContent))
{
repeatContent = output.Content;
output.Content = string.Empty;
repeatContent = content;
}
for (int i = 0; i < RepeatContent; i++)

3
test/WebSites/ActivatorWebSite/TagHelpers/TitleTagHelper.cs
View File

@ -9,7 +9,6 @@ using Microsoft.AspNet.Razor.TagHelpers;
namespace ActivatorWebSite.TagHelpers
{
[HtmlElementName("body")]
[ContentBehavior(ContentBehavior.Prepend)]
public class TitleTagHelper : TagHelper
{
[Activate]
@ -23,7 +22,7 @@ namespace ActivatorWebSite.TagHelpers
var builder = new TagBuilder("h2");
var title = ViewContext.ViewBag.Title;
builder.InnerHtml = HtmlHelper.Encode(title);
output.Content = builder.ToString();
output.PreContent = builder.ToString();
}
}
}