Generic types for XAML compiled bindings (#2748)

* Generic type support for x:DataType and x:Type.

* Fix bookmark.

* Edits.

docs/fundamentals/data-binding/compiled-bindings.md

@@ -1,7 +1,7 @@
 ---
 title: "Compiled bindings"
 description: "Compiled bindings can be used to improve data binding performance in .NET MAUI applications."
-ms.date: 11/14/2024
+ms.date: 01/27/2025
 ---
 
 # Compiled bindings
@@ -136,6 +136,30 @@ The following example demonstrates correctly setting the `x:DataType` on a <xref
 
 While this example sets the `x:DataType` attribute to a string literal, it can also be set to a type with the `x:Type` markup extension. For more information about the `x:Type` markup extension, see [x:Type Markup Extension](~/xaml/markup-extensions/consume.md#xtype-markup-extension).
 
+### Compile bindings that specify a generic type
+
+Generic types can be specified with the `x:DataType` attribute by specifying the generic constraint as a prefixed string argument in parentheses:
+
+```xaml
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             xmlns:local="clr-namespace:MyMauiApp"
+             x:Class="MyMauiApp.MyPage"
+             x:DataType="local:MyViewModel(x:Boolean)">
+    ...
+</ContentPage>
+```
+
+Multiple type arguments can be specified as prefixed string arguments, delimited by a comma:
+
+```xaml
+<DataTemplate x:DataType="local:MyType(local:MyObject,x:Boolean)">
+    ...
+</DataTemplate>
+```
+
+For more information about generics in XAML, see [Generics](~/xaml/generics.md).
+
 ::: moniker range=">=net-maui-9.0"
 
 ### Compile bindings that define the `Source` property

docs/xaml/generics.md

@@ -1,7 +1,7 @@
 ---
 title: "Generics"
 description: ".NET MAUI XAML provides support for consuming generic CLR types by specifying the generic constraints as type arguments."
-ms.date: 01/24/2022
+ms.date: 01/27/2025
 ---
 
 # Generics
@@ -11,13 +11,15 @@ ms.date: 01/24/2022
 Type arguments are specified as a string, and are typically prefixed, such as `sys:String` and `sys:Int32`. Prefixing is required because the typical types of CLR generic constraints come from libraries that are not mapped to the default .NET MAUI namespaces. However, the XAML 2009 built-in types such as `x:String` and `x:Int32`, can also be specified as type arguments, where `x` is the XAML language namespace for XAML 2009. For more information about the XAML 2009 built-in types, see [XAML 2009 Language Primitives](/dotnet/desktop-wpf/xaml-services/types-for-primitives#xaml-2009-language-primitives).
 
 > [!IMPORTANT]
-> Defining generic classes in .NET MAUI XAML, with the `x:TypeArguments` directive, is unsupported.
+> Defining generic types in .NET MAUI XAML, with the `x:TypeArguments` directive, is unsupported.
 
 Multiple type arguments can be specified by using a comma delimiter. In addition, if a generic constraint uses generic types, the nested constraint type arguments should be contained in parentheses.
 
 > [!NOTE]
 > The `x:Type` markup extension supplies a Common Language Runtime (CLR) type reference for a generic type, and has a similar function to the `typeof` operator in C#. For more information, see [x:Type markup extension](~/xaml/markup-extensions/consume.md#xtype-markup-extension).
 
+For information about specifying generic types in .NET MAUI XAML, with the `x:DataType` and `x:Type` directives, see [Compile bindings that specify a generic type](~/fundamentals/data-binding/compiled-bindings.md#compile-bindings-that-specify-a-generic-type) and [x:Type markup extension](~/xaml/markup-extensions/consume.md#xtype-markup-extension).
+
 ## Single primitive type argument
 
 A single primitive type argument can be specified as a prefixed string argument using the `x:TypeArguments` directive:

docs/xaml/markup-extensions/consume.md

@@ -1,7 +1,7 @@
 ---
 title: "Consume XAML markup extensions"
 description: ".NET MAUI XAML markup extensions enhance the power and flexibility of XAML by allowing element attributes to be set from a variety of sources."
-ms.date: 04/18/2023
+ms.date: 01/27/2025
 ---
 
 # Consume XAML markup extensions
@@ -221,6 +221,24 @@ When a <xref:Microsoft.Maui.Controls.Button> is pressed a new instance of the `C
 
 :::image type="content" source="media/consume/typedemo.png" alt-text="x:Type demo.":::
 
+Generic types can be specified with the `x:Type` markup extension by specifying the generic constraint as a prefixed string argument in parentheses:
+
+```xaml
+<x:Array Type="{x:Type local:MyType(local:MyObject)}">
+    ...
+</x:Array>
+```
+
+Multiple type arguments can be specified as prefixed string arguments, delimited by a comma:
+
+```xaml
+<x:Array Type="{x:Type local:MyType(local:MyObject,x:Boolean)}">
+    ...
+</x:Array>
+```
+
+For more information about generics in XAML, see [Generics](~/xaml/generics.md).
+
 ## x:Array markup extension
 
 The `x:Array` markup extension enables you to define an array in markup. It is supported by the <xref:Microsoft.Maui.Controls.Xaml.ArrayExtension> class, which defines two properties: