feat(xBind): Enhanced support for x:Bind casting expressions

doc/articles/features/windows-ui-xaml-xbind.md

@@ -89,8 +89,21 @@ Uno supports the [`x:Bind`](https://docs.microsoft.com/en-us/windows/uwp/xaml-pl
   ```
 
 - Type casts
-  ```xml
-  <TextBox FontFamily="{x:Bind (FontFamily)MyComboBox.SelectedValue}" />
+  - ```xml
+    <TextBox FontFamily="{x:Bind (FontFamily)MyComboBox.SelectedValue}" />
+    ```
+  - ```xml
+    <TextBox Text="{x:Bind (x:String)MyObject}" />
+    ```
+  - ```xml
+    <TextBox Text="{x:Bind MyFunction((x:String)MyObject, (x:String)MyObject)}" />
+    ```
+  - ```xml
+    <TextBox Tag="{x:Bind ((x:String)MyObject).Length}" />
+    ```
+  where this methods is available in the code behind:
+  ```csharp
+  public void MyFunction(string p1, string p2) { }
   ```
 
 - [Pathless casting](https://learn.microsoft.com/en-us/windows/uwp/xaml-platform/x-bind-markup-extension#pathless-casting)

src/SourceGenerators/Uno.UI.SourceGenerators.Tests.Shared/Given_XBindRewriter.cs

@@ -27,6 +27,9 @@ public class Given_XBindRewriter
 		[DataRow("ctx", "MyNameSpace.Static2.MyFunction(MyProperty)", "MyNameSpace.Static2.MyFunction(ctx.MyProperty)")]
 		[DataRow("ctx", "MyFunction(MyProperty)", "ctx.MyFunction(ctx.MyProperty)")]
 		[DataRow("ctx", "", "ctx")]
+
+		// Type Casts
+		[DataRow("ctx", "(FontFamily)Value", "(FontFamily)ctx.Value")]
 		[DataRow("ctx", "(FontFamily)a.Value", "(FontFamily)ctx.a.Value")]
 		[DataRow("ctx", "(global::System.Int32)a.Value", "(global::System.Int32)ctx.a.Value")]
 
@@ -41,7 +44,9 @@ public class Given_XBindRewriter
 		[DataRow("ctx", "System.String.Format('{0:X8}', AdornerCanvas.(MyNamespace.FrameworkElementExtensions.ActualWidth))", "System.String.Format('{0:X8}', MyNamespace.FrameworkElementExtensions.GetActualWidth(ctx.AdornerCanvas))")]
 
 		// Not supported https://github.com/unoplatform/uno/issues/5061
-		// [DataRow("ctx", "MyFunction((global::System.Int32)MyProperty)", "ctx.MyFunction((global::System.Int32)ctx.MyProperty)")]
+		[DataRow("ctx", "MyFunction((global::System.Int32)MyProperty)", "ctx.MyFunction((global::System.Int32)ctx.MyProperty)")]
+		[DataRow("ctx", "MyFunction((global::System.Int32)MyProperty.Inner)", "ctx.MyFunction((global::System.Int32)ctx.MyProperty.Inner)")]
+		[DataRow("ctx", "((MyClass)MyProperty).Test", "((MyClass)ctx.MyProperty).Test")]
 
 		// Main class (without context)
 		[DataRow("", "MyProperty.A", "MyProperty.A")]

src/SourceGenerators/Uno.UI.SourceGenerators/XamlGenerator/Utils/XBindExpressionParser.cs

@@ -104,8 +104,13 @@ private string ContextBuilder
 				var isPathLessCast = Helpers.IsPathLessCast(node);
 				var isAttachedPropertySyntax = Helpers.IsAttachedPropertySyntax(node);
 				var isInsideAttachedPropertySyntax = Helpers.IsInsideAttachedPropertySyntax(node);
+                var isParenthesizedExpression = node.Expression is ParenthesizedExpressionSyntax;
 
-				if (e != null && isValidParent && !_isStaticMember(node.Expression.ToFullString()) && !isParentMemberStatic)
+                if (e!= null
+					&& isValidParent
+					&& !_isStaticMember(node.Expression.ToFullString())
+					&& !isParentMemberStatic
+					&& !isParenthesizedExpression)
 				{
 					if (isPathLessCast.result)
 					{
@@ -145,9 +150,15 @@ private string ContextBuilder
 			public override SyntaxNode? VisitIdentifierName(IdentifierNameSyntax node)
 			{
 				var isInsideCast = Helpers.IsInsideCast(node);
-				var isValidParent = !Helpers.IsInsideMethod(node).result
-					&& !Helpers.IsInsideMemberAccessExpression(node).result
-					&& !isInsideCast.result;
+				var isValidParent =
+					(
+						!Helpers.IsInsideMethod(node).result
+						&& !Helpers.IsInsideMemberAccessExpression(node).result
+						&& !isInsideCast.result
+					)
+					|| Helpers.IsInsideCastWithParentheses(node).result
+					|| Helpers.IsInsideCastAsArrowClause(node).result
+					|| Helpers.IsInsideCastAsMethodArgument(node).result;
 
 				if (isValidParent && !_isStaticMember(node.ToFullString()))
 				{
@@ -231,22 +242,7 @@ internal static ExpressionSyntax ParseMethodBody(string body)
 					.Expression;
 
 			internal static (bool result, MemberAccessExpressionSyntax? memberAccess) IsInsideMemberAccessExpression(SyntaxNode node)
-			{
-				var currentNode = node.Parent;
-
-				do
-				{
-					if (currentNode is MemberAccessExpressionSyntax memberAccess)
-					{
-						return (true, memberAccess);
-					}
-
-					currentNode = currentNode?.Parent;
-				}
-				while (currentNode != null);
-
-				return (false, null);
-			}
+				=> IsInside(node, n => n as MemberAccessExpressionSyntax);
 
 			internal static (bool result, InvocationExpressionSyntax? expression) IsInsideMethod(SyntaxNode node)
 			{
@@ -270,12 +266,36 @@ internal static (bool result, InvocationExpressionSyntax? expression) IsInsideMe
 			}
 
 			internal static (bool result, CastExpressionSyntax? expression) IsInsideCast(SyntaxNode node)
+				=> IsInside(node, n => n as CastExpressionSyntax);
+
+			internal static (bool result, CastExpressionSyntax? expression) IsInsideCastWithParentheses(SyntaxNode node)
+				=> IsInside(
+					node,
+					n => n is CastExpressionSyntax cast
+						&& cast.Parent is ParenthesizedExpressionSyntax
+						&& cast.Expression == node ? cast : null);
+
+			internal static (bool result, CastExpressionSyntax? expression) IsInsideCastAsMethodArgument(SyntaxNode node)
+				=> IsInside(
+					node,
+					n => n is CastExpressionSyntax cast
+						&& cast.Parent is ArgumentSyntax
+						&& cast.Expression == node ? cast : null);
+
+			internal static (bool result, CastExpressionSyntax? expression) IsInsideCastAsArrowClause(SyntaxNode node)
+				=> IsInside(
+					node,
+					n => n is CastExpressionSyntax cast
+						&& cast.Parent is ArrowExpressionClauseSyntax
+						&& cast.Expression == node ? cast : null);
+
+			internal static (bool result, T? expression) IsInside<T>(SyntaxNode node, Func<SyntaxNode?, T?> predicate) where T: SyntaxNode
 			{
 				var currentNode = node.Parent;
 
 				do
 				{
-					if (currentNode is CastExpressionSyntax cast)
+					if (predicate(currentNode) is { } cast)
 					{
 						return (true, cast);
 					}

src/Uno.UI.Tests/Windows_UI_Xaml_Data/xBindTests/Controls/Binding_TypeCast.xaml

@@ -0,0 +1,20 @@
+<UserControl
+    x:Class="Uno.UI.Tests.Windows_UI_Xaml_Data.xBindTests.Controls.Binding_TypeCast"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:Uno.UI.Tests.Windows_UI_Xaml_Data.xBindTests.Controls">
+    <Grid>
+		<TextBlock x:Name="tb01"
+				   x:FieldModifier="public"
+				   Text="{x:Bind (x:String)MyObject}"/>
+		<TextBlock x:Name="tb02"
+				   x:FieldModifier="public"
+				   Text="{x:Bind MyMethod((x:String)MyObject)}"/>
+		<TextBlock x:Name="tb03"
+				   x:FieldModifier="public"
+				   Text="{x:Bind MyMethod2((x:String)MyObject, (x:String)MyObject)}" />
+		<TextBlock x:Name="tb04"
+				   x:FieldModifier="public"
+				   Tag="{x:Bind ((x:String)MyObject).Length}" />
+	</Grid>
+</UserControl>

src/Uno.UI.Tests/Windows_UI_Xaml_Data/xBindTests/Controls/Binding_TypeCast.xaml.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Runtime.InteropServices.WindowsRuntime;
+using Windows.Foundation;
+using Windows.Foundation.Collections;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Controls.Primitives;
+using Windows.UI.Xaml.Data;
+using Windows.UI.Xaml.Input;
+using Windows.UI.Xaml.Media;
+using Windows.UI.Xaml.Navigation;
+
+// The User Control item template is documented at https://go.microsoft.com/fwlink/?LinkId=234236
+
+namespace Uno.UI.Tests.Windows_UI_Xaml_Data.xBindTests.Controls
+{
+	public sealed partial class Binding_TypeCast : UserControl
+	{
+		public Binding_TypeCast()
+		{
+			this.InitializeComponent();
+		}
+
+		public object MyObject => "42";
+
+		public string MyMethod(string myString)
+			=> myString;
+
+		public string MyMethod2(string myString, string myString2)
+			=> myString + myString2;
+	}
+}

src/Uno.UI.Tests/Windows_UI_Xaml_Data/xBindTests/Controls/Binding_TypeCast_DataTemplate.xaml

@@ -0,0 +1,28 @@
+<UserControl
+    x:Class="Uno.UI.Tests.Windows_UI_Xaml_Data.xBindTests.Controls.Binding_TypeCast_DataTemplate"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:Uno.UI.Tests.Windows_UI_Xaml_Data.xBindTests.Controls">
+	<ContentControl x:Name="root"
+					x:FieldModifier="public">
+		<ContentControl.ContentTemplate>
+			<DataTemplate x:DataType="local:Binding_TypeCast_DataTemplate_Data">
+				<StackPanel>
+					<TextBlock x:Name="tb01"
+							   x:FieldModifier="public"
+							   Text="{x:Bind (x:String)MyObject}" />
+					<TextBlock x:Name="tb02"
+							   x:FieldModifier="public"
+							   Text="{x:Bind MyMethod((x:String)MyObject)}" />
+					<TextBlock x:Name="tb03"
+							   x:FieldModifier="public"
+							   Text="{x:Bind MyMethod2((x:String)MyObject, (x:String)MyObject)}" />
+					<TextBlock x:Name="tb04"
+							   x:FieldModifier="public"
+							   Tag="{x:Bind ((x:String)MyObject).Length}" />
+
+				</StackPanel>
+			</DataTemplate>
+		</ContentControl.ContentTemplate>
+	</ContentControl>
+</UserControl>

src/Uno.UI.Tests/Windows_UI_Xaml_Data/xBindTests/Controls/Binding_TypeCast_DataTemplate.xaml.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Runtime.InteropServices.WindowsRuntime;
+using Windows.Foundation;
+using Windows.Foundation.Collections;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Controls.Primitives;
+using Windows.UI.Xaml.Data;
+using Windows.UI.Xaml.Input;
+using Windows.UI.Xaml.Media;
+using Windows.UI.Xaml.Navigation;
+
+// The User Control item template is documented at https://go.microsoft.com/fwlink/?LinkId=234236
+
+namespace Uno.UI.Tests.Windows_UI_Xaml_Data.xBindTests.Controls
+{
+	public sealed partial class Binding_TypeCast_DataTemplate : UserControl
+	{
+		public Binding_TypeCast_DataTemplate()
+		{
+			this.InitializeComponent();
+		}
+	}
+
+	public partial class Binding_TypeCast_DataTemplate_Data
+	{
+		public object MyObject => "42";
+
+		public string MyMethod(string myString)
+			=> myString;
+
+		public string MyMethod2(string myString, string myString2)
+			=> myString + myString2;
+	}
+}

src/Uno.UI.Tests/Windows_UI_Xaml_Data/xBindTests/Given_xBind_Binding.cs

@@ -1264,6 +1264,42 @@ public async Task When_NullableRecordStruct()
 			Assert.AreEqual("42", SUT.tb1.Text);
 		}
 
+		[TestMethod]
+		public async Task When_TypeCast()
+		{
+			var SUT = new Binding_TypeCast();
+
+			SUT.ForceLoaded();
+
+			Assert.AreEqual("42", SUT.tb01.Text);
+			Assert.AreEqual("42", SUT.tb02.Text);
+			Assert.AreEqual("4242", SUT.tb03.Text);
+			Assert.AreEqual(2, SUT.tb04.Tag);
+		}
+
+		[TestMethod]
+		public async Task When_TypeCast_DataTemplate()
+		{
+			var SUT = new Binding_TypeCast_DataTemplate();
+
+			var root = SUT.FindName("root") as FrameworkElement;
+			var dc = new Binding_TypeCast_DataTemplate_Data();
+			root.DataContext = dc;
+
+			SUT.ForceLoaded();
+			root.ForceLoaded();
+
+			var tb01 = SUT.FindName("tb01") as TextBlock;
+			var tb02 = SUT.FindName("tb02") as TextBlock;
+			var tb03 = SUT.FindName("tb03") as TextBlock;
+			var tb04 = SUT.FindName("tb04") as TextBlock;
+
+			Assert.AreEqual("42", tb01.Text);
+			Assert.AreEqual("42", tb02.Text);
+			Assert.AreEqual("4242", tb03.Text);
+			Assert.AreEqual(2, tb04.Tag);
+		}
+
 		[TestMethod]
 		public async Task When_PathLessCasting()
 		{