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Components that accept bind-Something can request SomethingExpression (dotnet/aspnetcore-tooling#213) 

* In binding to components, automatically supply FooExpression when requested

* Fix tests

* CR feedback
\n\nCommit migrated from ca9de74f4e
This commit is contained in:
Steve Sanderson 2019-02-18 09:37:41 +00:00 committed by GitHub
parent 0ab2a1e586
commit 82d850d3a7
6 changed files with 87 additions and 5 deletions
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2
src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/BlazorMetadata.cs
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@ -24,6 +24,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
public readonly static string ValueAttribute = "Blazor.Bind.ValueAttribute";
public readonly static string ChangeAttribute = "Blazor.Bind.ChangeAttribute";
public readonly static string ExpressionAttribute = "Blazor.Bind.ExpressionAttribute";
}
public static class ChildContent

53
src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentBindLoweringPass.cs
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@ -148,11 +148,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
{
// Bind works similarly to a macro, it always expands to code that the user could have written.
//
// For the nodes that are related to the bind-attribute rewrite them to look like a pair of
// For the nodes that are related to the bind-attribute rewrite them to look like a set of
// 'normal' HTML attributes similar to the following transformation.
//
// Input: <MyComponent bind-Value="@currentCount" />
// Output: <MyComponent Value ="...<get the value>..." ValueChanged ="... <set the value>..." />
// Output: <MyComponent Value ="...<get the value>..." ValueChanged ="... <set the value>..." ValueExpression ="() => ...<get the value>..." />
//
// This means that the expression that appears inside of 'bind' must be an LValue or else
// there will be errors. In general the errors that come from C# in this case are good enough
@ -171,8 +171,10 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
node.AttributeName,
out var valueAttributeName,
out var changeAttributeName,
out var expressionAttributeName,
out var valueAttribute,
out var changeAttribute))
out var changeAttribute,
out var expressionAttribute))
{
// Skip anything we can't understand. It's important that we don't crash, that will bring down
// the build.
@ -340,7 +342,32 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
changeNode.Children[0].Children.Add(changeExpressionTokens[i]);
}
return new[] { valueNode, changeNode };
// Finally, also emit a node for the "Expression" attribute, but only if the target
// component is defined to accept one
ComponentAttributeIntermediateNode expressionNode = null;
if (expressionAttribute != null)
{
expressionNode = new ComponentAttributeIntermediateNode(node)
{
AttributeName = expressionAttributeName,
BoundAttribute = expressionAttribute,
PropertyName = expressionAttribute.GetPropertyName(),
TagHelper = node.TagHelper,
TypeName = expressionAttribute.IsWeaklyTyped() ? null : expressionAttribute.TypeName,
};
expressionNode.Children.Clear();
expressionNode.Children.Add(new CSharpExpressionIntermediateNode());
expressionNode.Children[0].Children.Add(new IntermediateToken()
{
Content = $"() => {original.Content}",
Kind = TokenKind.CSharp
});
}
return expressionNode == null
? new[] { valueNode, changeNode }
: new[] { valueNode, changeNode, expressionNode };
}
}
@ -394,11 +421,15 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
string attributeName,
out string valueAttributeName,
out string changeAttributeName,
out string expressionAttributeName,
out BoundAttributeDescriptor valueAttribute,
out BoundAttributeDescriptor changeAttribute)
out BoundAttributeDescriptor changeAttribute,
out BoundAttributeDescriptor expressionAttribute)
{
valueAttribute = null;
changeAttribute = null;
expressionAttribute = null;
expressionAttributeName = null;
// Even though some of our 'bind' tag helpers specify the attribute names, they
// should still satisfy one of the valid syntaxes.
@ -415,6 +446,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
// We expect 1 bind tag helper per-node.
valueAttributeName = node.TagHelper.GetValueAttributeName() ?? valueAttributeName;
changeAttributeName = node.TagHelper.GetChangeAttributeName() ?? changeAttributeName;
expressionAttributeName = node.TagHelper.GetExpressionAttributeName() ?? expressionAttributeName;
// We expect 0-1 components per-node.
var componentTagHelper = (parent as ComponentIntermediateNode)?.Component;
@ -437,6 +469,12 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
changeAttributeName = valueAttributeName + "Changed";
}
// Likewise for the expression attribute
if (expressionAttributeName == null)
{
expressionAttributeName = valueAttributeName + "Expression";
}
for (var i = 0; i < componentTagHelper.BoundAttributes.Count; i++)
{
var attribute = componentTagHelper.BoundAttributes[i];
@ -450,6 +488,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
{
changeAttribute = attribute;
}
if (string.Equals(expressionAttributeName, attribute.Name))
{
expressionAttribute = attribute;
}
}
return true;

11
src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/TagHelperDescriptorExtensions.cs
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@ -95,6 +95,17 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
return result;
}
public static string GetExpressionAttributeName(this TagHelperDescriptor tagHelper)
{
if (tagHelper == null)
{
throw new ArgumentNullException(nameof(tagHelper));
}
tagHelper.Metadata.TryGetValue(BlazorMetadata.Bind.ExpressionAttribute, out var result);
return result;
}
public static bool IsChildContentTagHelper(this TagHelperDescriptor tagHelper)
{
if (tagHelper == null)

20
src/Razor/Microsoft.CodeAnalysis.Razor/src/BindTagHelperDescriptorProvider.cs
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@ -351,6 +351,8 @@ namespace Microsoft.CodeAnalysis.Razor
//
// The easiest way to figure this out without a lot of backtracking is to look for `FooChanged` and then
// try to find a matching "Foo".
//
// We also look for a corresponding FooExpression attribute, though its presence is optional.
for (var i = 0; i < tagHelper.BoundAttributes.Count; i++)
{
var changeAttribute = tagHelper.BoundAttributes[i];
@ -360,12 +362,25 @@ namespace Microsoft.CodeAnalysis.Razor
}
BoundAttributeDescriptor valueAttribute = null;
BoundAttributeDescriptor expressionAttribute = null;
var valueAttributeName = changeAttribute.Name.Substring(0, changeAttribute.Name.Length - "Changed".Length);
var expressionAttributeName = valueAttributeName + "Expression";
for (var j = 0; j < tagHelper.BoundAttributes.Count; j++)
{
if (tagHelper.BoundAttributes[j].Name == valueAttributeName && !tagHelper.BoundAttributes[j].IsDelegateProperty())
{
valueAttribute = tagHelper.BoundAttributes[j];
}
if (tagHelper.BoundAttributes[j].Name == expressionAttributeName)
{
expressionAttribute = tagHelper.BoundAttributes[j];
}
if (valueAttribute != null && expressionAttribute != null)
{
// We found both, so we can stop looking now
break;
}
}
@ -388,6 +403,11 @@ namespace Microsoft.CodeAnalysis.Razor
builder.Metadata[BlazorMetadata.Bind.ValueAttribute] = valueAttribute.Name;
builder.Metadata[BlazorMetadata.Bind.ChangeAttribute] = changeAttribute.Name;
if (expressionAttribute != null)
{
builder.Metadata[BlazorMetadata.Bind.ExpressionAttribute] = expressionAttribute.Name;
}
// WTE has a bug 15.7p1 where a Tag Helper without a display-name that looks like
// a C# property will crash trying to create the toolips.
builder.SetTypeName(tagHelper.GetTypeName());

5
src/Razor/Microsoft.CodeAnalysis.Razor/test/BindTagHelperDescriptorProviderTest.cs
View File

@ -16,6 +16,7 @@ namespace Microsoft.CodeAnalysis.Razor
// Arrange
var compilation = BaseCompilation.AddSyntaxTrees(Parse(@"
using System;
using System.Linq.Expressions;
using Microsoft.AspNetCore.Components;
namespace Test
@ -31,6 +32,9 @@ namespace Test
[Parameter]
Action<string> MyPropertyChanged { get; set; }
[Parameter]
Expression<Func<string>> MyPropertyExpression { get; set; }
}
}
"));
@ -69,6 +73,7 @@ namespace Test
Assert.Equal("MyProperty", bind.Metadata[BlazorMetadata.Bind.ValueAttribute]);
Assert.Equal("MyPropertyChanged", bind.Metadata[BlazorMetadata.Bind.ChangeAttribute]);
Assert.Equal("MyPropertyExpression", bind.Metadata[BlazorMetadata.Bind.ExpressionAttribute]);
Assert.Equal(
"Binds the provided expression to the 'MyProperty' property and a change event " +

1
src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorIntegrationTestBase.cs
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@ -36,6 +36,7 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
{
typeof(System.Runtime.AssemblyTargetedPatchBandAttribute).Assembly, // System.Runtime
typeof(Enumerable).Assembly, // Other .NET fundamental types
typeof(System.Linq.Expressions.Expression).Assembly,
typeof(ComponentBase).Assembly,
};