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Try to infer DataContext type from the $parent and #named compiled binding path parts #17204

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Merged
merged 7 commits into from
Oct 11, 2024
Merged

Try to infer DataContext type from the $parent and #named compiled binding path parts #17204

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d3bce52
Try to infer DataContext type from #named binding nodes
maxkatz6 Oct 6, 2024
5d773b1
Try to infer DataContext type from $parent binding nodes
maxkatz6 Oct 6, 2024
5bc04b3
Use new syntax in the repo (Rider still marks it as an error)
maxkatz6 Oct 6, 2024
118280c
Add tests ensuring type casing still works
maxkatz6 Oct 7, 2024
19dc862
Merge branch 'master' into binding-datacontext-inheritance
maxkatz6 Oct 10, 2024
46d5138
Fix $parent regression
maxkatz6 Oct 10, 2024
9c0e0ba
Make new tests StringSyntax compatible
maxkatz6 Oct 10, 2024
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3 changes: 2 additions & 1 deletion src/Avalonia.Diagnostics/Diagnostics/Views/ControlDetailsView.xaml
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Original file line number Diff line number Diff line change
Expand Up @@ -177,7 +177,8 @@
<MultiBinding Converter="{x:Static BoolConverters.And}">
<MultiBinding Converter="{x:Static BoolConverters.Or}" >
<Binding Path="IsActive" />
<Binding Path="#Main.((vm:ControlDetailsViewModel)DataContext).ShowInactiveFrames" />
<!-- Rider marks it as an error, because it doesn't know about new binding rules yet. -->
<Binding Path="#Main.DataContext.ShowInactiveFrames" />
</MultiBinding>
<Binding Path="IsVisible" />
</MultiBinding>
Expand Down
104 changes: 74 additions & 30 deletions src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/XamlIlBindingPathHelper.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -197,8 +197,13 @@ private static XamlIlBindingPathNode TransformBindingPath(AstTransformationConte

if (avaloniaPropertyFieldMaybe != null)
{
nodes.Add(new XamlIlAvaloniaPropertyPropertyPathElementNode(avaloniaPropertyFieldMaybe,
XamlIlAvaloniaPropertyHelper.GetAvaloniaPropertyType(avaloniaPropertyFieldMaybe, context.GetAvaloniaTypes(), lineInfo)));
var isDataContextProperty = avaloniaPropertyFieldMaybe.Name == "DataContextProperty" && Equals(avaloniaPropertyFieldMaybe.DeclaringType, context.GetAvaloniaTypes().StyledElement);
var propertyType = isDataContextProperty
? (nodes.LastOrDefault() as IXamlIlBindingPathNodeWithDataContextType)?.DataContextType
: null;
propertyType ??= XamlIlAvaloniaPropertyHelper.GetAvaloniaPropertyType(avaloniaPropertyFieldMaybe, context.GetAvaloniaTypes(), lineInfo);

nodes.Add(new XamlIlAvaloniaPropertyPropertyPathElementNode(avaloniaPropertyFieldMaybe, propertyType));
}
else if (GetAllDefinedProperties(targetType).FirstOrDefault(p => p.Name == propName.PropertyName) is IXamlProperty clrProperty)
{
Expand Down Expand Up @@ -297,49 +302,70 @@ private static XamlIlBindingPathNode TransformBindingPath(AstTransformationConte
nodes.Add(new TemplatedParentPathElementNode(templatedParentType.GetClrType()));
break;
case BindingExpressionGrammar.AncestorNode ancestor:
if (ancestor.Namespace is null && ancestor.TypeName is null)
var styledElement = context.GetAvaloniaTypes().StyledElement;
var ancestorTypeFilter = !(ancestor.Namespace is null && ancestor.TypeName is null) ? GetType(ancestor.Namespace, ancestor.TypeName) : null;

var ancestorNode = context
.ParentNodes()
.OfType<XamlAstConstructableObjectNode>()
.Where(x => styledElement.IsAssignableFrom(x.Type.GetClrType()))
.Skip(1)
.Where(x => ancestorTypeFilter is not null
? ancestorTypeFilter.IsAssignableFrom(x.Type.GetClrType()) : true)
.ElementAtOrDefault(ancestor.Level);

IXamlType? dataContextType = null;
if (ancestorNode is not null)
{
var styledElementType = context.GetAvaloniaTypes().StyledElement;
var ancestorType = context
.ParentNodes()
.OfType<XamlAstConstructableObjectNode>()
.Where(x => styledElementType.IsAssignableFrom(x.Type.GetClrType()))
.Skip(1)
.ElementAtOrDefault(ancestor.Level)
?.Type.GetClrType();

if (ancestorType is null)
var isSkipping = true;
foreach (var node in context.ParentNodes())
{
throw new XamlX.XamlTransformException("Unable to resolve implicit ancestor type based on XAML tree.", lineInfo);
if (node == ancestorNode)
isSkipping = false;
if (node is AvaloniaNameScopeRegistrationXamlIlNode)
break;
if (!isSkipping && node is AvaloniaXamlIlDataContextTypeMetadataNode metadataNode)
{
dataContextType = metadataNode.DataContextType;
break;
}
}

nodes.Add(new FindAncestorPathElementNode(ancestorType, ancestor.Level));
}
else

// We need actual ancestor for a correct DataContextType,
// but since in current design bindings do a double-work by enumerating the tree,
// we want to keep original ancestor type filter, if it was present.
var bindingAncestorType = ancestorTypeFilter is not null
? ancestorTypeFilter
: ancestorNode?.Type.GetClrType();

if (bindingAncestorType is null)
{
nodes.Add(new FindAncestorPathElementNode(GetType(ancestor.Namespace, ancestor.TypeName), ancestor.Level));
throw new XamlX.XamlTransformException("Unable to resolve implicit ancestor type based on XAML tree.", lineInfo);
}

nodes.Add(new FindAncestorPathElementNode(bindingAncestorType, ancestor.Level, dataContextType));
break;
case BindingExpressionGrammar.NameNode elementName:
IXamlType? elementType = null;
IXamlType? elementType = null, dataType = null;
foreach (var deferredContent in context.ParentNodes().OfType<NestedScopeMetadataNode>())
{
elementType = ScopeRegistrationFinder.GetTargetType(deferredContent, elementName.Name);
(elementType, dataType) = ScopeRegistrationFinder.GetTargetType(deferredContent, elementName.Name) ?? default;
if (!(elementType is null))
{
break;
}
}
if (elementType is null)
{
elementType = ScopeRegistrationFinder.GetTargetType(context.ParentNodes().Last(), elementName.Name);
(elementType, dataType) = ScopeRegistrationFinder.GetTargetType(context.ParentNodes().Last(), elementName.Name) ?? default;
}

if (elementType is null)
{
throw new XamlX.XamlTransformException($"Unable to find element '{elementName.Name}' in the current namescope. Unable to use a compiled binding with a name binding if the name cannot be found at compile time.", lineInfo);
}
nodes.Add(new ElementNamePathElementNode(elementName.Name, elementType));
nodes.Add(new ElementNamePathElementNode(elementName.Name, elementType, dataType));
break;
case BindingExpressionGrammar.TypeCastNode typeCastNode:
var castType = GetType(typeCastNode.Namespace, typeCastNode.TypeName);
Expand Down Expand Up @@ -420,8 +446,9 @@ private ScopeRegistrationFinder(string name)
string Name { get; }

IXamlType? TargetType { get; set; }
IXamlType? DataContextType { get; set; }

public static IXamlType? GetTargetType(IXamlAstNode namescopeRoot, string name)
public static (IXamlType Target, IXamlType? DataContextType)? GetTargetType(IXamlAstNode namescopeRoot, string name)
{
// If we start from the nested scope - skip it.
if (namescopeRoot is NestedScopeMetadataNode scope)
Expand All @@ -431,7 +458,7 @@ private ScopeRegistrationFinder(string name)

var finder = new ScopeRegistrationFinder(name);
namescopeRoot.Visit(finder);
return finder.TargetType;
return finder.TargetType is not null ? (finder.TargetType, DataType: finder.DataContextType) : null;
}

void IXamlAstVisitor.Pop()
Expand All @@ -455,12 +482,20 @@ void IXamlAstVisitor.Push(IXamlAstNode node)
IXamlAstNode IXamlAstVisitor.Visit(IXamlAstNode node)
{
// Ignore name registrations, if we are inside of the nested namescope.
if (_childScopesStack.Count == 0 && node is AvaloniaNameScopeRegistrationXamlIlNode registration)
if (_childScopesStack.Count == 0)
{
if (registration.Name is XamlAstTextNode text && text.Text == Name)
if (node is AvaloniaNameScopeRegistrationXamlIlNode registration
&& registration.Name is XamlAstTextNode text && text.Text == Name)
{
TargetType = registration.TargetType;
}
// We are visiting nodes top to bottom.
// If we have already found target type by its name,
// it means all next nodes will be below, and not applicable for data context inheritance.
else if (TargetType is null && node is AvaloniaXamlIlDataContextTypeMetadataNode dataContextTypeMetadata)
{
DataContextType = dataContextTypeMetadata.DataContextType;
}
}
return node;
}
Expand All @@ -473,6 +508,11 @@ interface IXamlIlBindingPathElementNode
void Emit(XamlIlEmitContext context, IXamlILEmitter codeGen);
}

interface IXamlIlBindingPathNodeWithDataContextType
{
IXamlType? DataContextType { get; }
}

class XamlIlNotPathElementNode : IXamlIlBindingPathElementNode
{
public XamlIlNotPathElementNode(IXamlType boolType)
Expand Down Expand Up @@ -533,17 +573,19 @@ public void Emit(XamlIlEmitContext context, IXamlILEmitter codeGen)
}
}

class FindAncestorPathElementNode : IXamlIlBindingPathElementNode
class FindAncestorPathElementNode : IXamlIlBindingPathElementNode, IXamlIlBindingPathNodeWithDataContextType
{
private readonly int _level;

public FindAncestorPathElementNode(IXamlType ancestorType, int level)
public FindAncestorPathElementNode(IXamlType ancestorType, int level, IXamlType? dataContextType)
{
Type = ancestorType;
_level = level;
DataContextType = dataContextType;
}

public IXamlType Type { get; }
public IXamlType? DataContextType { get; }

public void Emit(XamlIlEmitContext context, IXamlILEmitter codeGen)
{
Expand Down Expand Up @@ -573,17 +615,19 @@ public void Emit(XamlIlEmitContext context, IXamlILEmitter codeGen)
}
}

class ElementNamePathElementNode : IXamlIlBindingPathElementNode
class ElementNamePathElementNode : IXamlIlBindingPathElementNode, IXamlIlBindingPathNodeWithDataContextType
{
private readonly string _name;

public ElementNamePathElementNode(string name, IXamlType elementType)
public ElementNamePathElementNode(string name, IXamlType elementType, IXamlType? dataType)
{
_name = name;
Type = elementType;
DataContextType = dataType;
}

public IXamlType Type { get; }
public IXamlType? DataContextType { get; }

public void Emit(XamlIlEmitContext context, IXamlILEmitter codeGen)
{
Expand Down
156 changes: 156 additions & 0 deletions tests/Avalonia.Markup.Xaml.UnitTests/MarkupExtensions/CompiledBindingExtensionTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1282,6 +1282,28 @@ public void SupportParentInPath()
}
}

[Fact]
public void SupportsParentInPathWithTypeAndLevelFilter()
{
using (UnitTestApplication.Start(TestServices.StyledWindow))
{
var window = (Window)AvaloniaRuntimeXamlLoader.Load(@"
<Window xmlns='https://github.com/avaloniaui'
xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'>
<Border x:Name='p2'>
<Border x:Name='p1'>
<Button x:Name='p0'>
<TextBlock x:Name='textBlock' Text='{CompiledBinding $parent[Control;1].Name}' />
</Button>
</Border>
</Border>
</Window>");
var textBlock = window.GetControl<TextBlock>("textBlock");

Assert.Equal("p1", textBlock.Text);
}
}

[Fact]
public void SupportConverterWithParameter()
{
Expand Down Expand Up @@ -2175,6 +2197,140 @@ public void Can_Bind_Brush_To_Hex_String()
}
}

[Fact]
public void ResolvesElementNameDataContextTypeBasedOnContext()
{
using (UnitTestApplication.Start(TestServices.StyledWindow))
{
var window = (Window)AvaloniaRuntimeXamlLoader.Load(@"
<Window xmlns='https://github.com/avaloniaui'
xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.MarkupExtensions;assembly=Avalonia.Markup.Xaml.UnitTests'
x:DataType='local:TestDataContext'
x:Name='MyWindow'>
<TextBlock Text='{CompiledBinding ElementName=MyWindow, Path=DataContext.StringProperty}' Name='textBlock' />
</Window>");
var textBlock = window.GetControl<TextBlock>("textBlock");

var dataContext = new TestDataContext
{
StringProperty = "foobar"
};

window.DataContext = dataContext;

Assert.Equal(dataContext.StringProperty, textBlock.Text);
}
}

[Fact]
public void ResolvesElementNameDataContextTypeBasedOnContextShortSyntax()
{
using (UnitTestApplication.Start(TestServices.StyledWindow))
{
var window = (Window)AvaloniaRuntimeXamlLoader.Load(@"
<Window xmlns='https://github.com/avaloniaui'
xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.MarkupExtensions;assembly=Avalonia.Markup.Xaml.UnitTests'
x:DataType='local:TestDataContext'
x:Name='MyWindow'>
<TextBlock Text='{CompiledBinding #MyWindow.DataContext.StringProperty}' Name='textBlock' />
</Window>");
var textBlock = window.GetControl<TextBlock>("textBlock");

var dataContext = new TestDataContext
{
StringProperty = "foobar"
};

window.DataContext = dataContext;

Assert.Equal(dataContext.StringProperty, textBlock.Text);
}
}

[Fact]
public void TypeCastWorksWithElementNameDataContext()
{
// By default, DataContext will infer DataType from the XAML context, which will be local:TestDataContext here.
// But developer should be able to re-define this type via type casing, if they know better.
using (UnitTestApplication.Start(TestServices.StyledWindow))
{
var window = (Window)AvaloniaRuntimeXamlLoader.Load(@"
<Window xmlns='https://github.com/avaloniaui'
xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.MarkupExtensions;assembly=Avalonia.Markup.Xaml.UnitTests'
x:DataType='local:TestDataContext'
x:Name='MyWindow'>
<Panel>
<TextBlock Text='{CompiledBinding $parent.((Button)DataContext).Tag}' Name='textBlock' />
</Panel>
</Window>");
var textBlock = window.GetControl<TextBlock>("textBlock");

var panelDataContext = new Button { Tag = "foo" };
((Panel)window.Content!).DataContext = panelDataContext;

Assert.Equal(panelDataContext.Tag, textBlock.Text);
}
}

[Fact]
public void ResolvesParentDataContextTypeBasedOnContext()
{
using (UnitTestApplication.Start(TestServices.StyledWindow))
{
var window = (Window)AvaloniaRuntimeXamlLoader.Load(@"
<Window xmlns='https://github.com/avaloniaui'
xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.MarkupExtensions;assembly=Avalonia.Markup.Xaml.UnitTests'
x:DataType='local:TestDataContext'
x:Name='MyWindow'>
<Panel>
<TextBlock Text='{CompiledBinding $parent[Panel].DataContext.StringProperty}' Name='textBlock' />
</Panel>
</Window>");
var textBlock = window.GetControl<TextBlock>("textBlock");

var dataContext = new TestDataContext
{
StringProperty = "foobar"
};

window.DataContext = dataContext;

Assert.Equal(dataContext.StringProperty, textBlock.Text);
}
}

[Fact]
public void ResolvesParentDataContextTypeBasedOnContextShortSyntax()
{
using (UnitTestApplication.Start(TestServices.StyledWindow))
{
var window = (Window)AvaloniaRuntimeXamlLoader.Load(@"
<Window xmlns='https://github.com/avaloniaui'
xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.MarkupExtensions;assembly=Avalonia.Markup.Xaml.UnitTests'
x:DataType='local:TestDataContext'
x:Name='MyWindow'>
<Panel>
<TextBlock Text='{CompiledBinding $parent.DataContext.StringProperty}' Name='textBlock' />
</Panel>
</Window>");
var textBlock = window.GetControl<TextBlock>("textBlock");

var dataContext = new TestDataContext
{
StringProperty = "foobar"
};

window.DataContext = dataContext;

Assert.Equal(dataContext.StringProperty, textBlock.Text);
}
}

static void Throws(string type, Action cb)
{
try
Expand Down
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