Add WinFormsWithIslandApp, a simple WinForms app that hosts Xaml in an Island

Samples/Islands/README.md

@@ -92,3 +92,38 @@ DispatcherQueueController on a dedicated rendering thread. (main.cpp)
 * Press Ctrl+Shift+B, or select **Build** \> **Build Solution**.
 * Press Ctrl+F5 to launch the app without attaching a debugger.
 * Press F5 to launch the app under a debugger.
+
+# WinForms Island App (cs-winforms-unpackaged)
+
+The cs-winforms-unpackaged directory has a sample shows how to add a WinAppSDK island with Xaml content to a WinForms app. 
+It was first created with the C# "Windows Forms App" template in Visual Studio, which yields a boilerplate WinForms app.
+
+This sample is an "unpackaged" app, so it will run like a WinForms/Win32 app does when built from the default templates.
+
+This sample uses Windows App SDK as a "framework package".  This means that the Windows App SDK runtime must be installed for it to run.
+
+## Prerequisites
+
+* See [System requirements for Windows app development](https://docs.microsoft.com/windows/apps/windows-app-sdk/system-requirements).
+* Make sure that your development environment is set up correctly—see [Install tools for developing apps for Windows 10 and Windows 11](https://docs.microsoft.com/windows/apps/windows-app-sdk/set-up-your-development-environment).
+
+## Building and running the WinForms Island sample
+
+* Open the solution file (`.sln`) in Visual Studio.
+* Press Ctrl+Shift+B, or select **Build** \> **Build Solution**.
+* Press Ctrl+F5 to launch the app (without attaching a debugger)
+    > Note: If the Windows App SDK runtime isn't installed on the machine, the user will see a message box directing them to a download link.
+* Press F5 to launch the app under a debugger.
+* To run from the command line or File Explorer, navigate to `bin/<arch>/<config>/net6.0-windows10.0.17763.0` directory and run WinFormsWithIslandApp.exe.
+* To deploy to another machine, copy the `bin/<arch>/<config>/net6.0-windows10.0.17763.0` directory to that machine and run WinFormsWithIslandApp.exe.  The sample
+runs on Windows version 17763 and later.
+
+In Visual Studio, you should also be able to see the DesktopWindowXamlSourceControl in the designer:
+
+![alt text](img/designer.png)
+
+When you launch the app, it should look like this:
+
+![alt text](img/screenshot.png)
+
+

Samples/Islands/cs-winforms-unpackaged/DesktopWindowXamlSourceControl.cs

@@ -0,0 +1,161 @@
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+using Microsoft.UI.Xaml.Hosting;
+using Microsoft.UI.Xaml.Media;
+using Microsoft.UI;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+using Windows.Foundation;
+
+namespace WinFormsWithIsland
+{
+    /// <summary>
+    /// This control hosts a DesktopWindowXamlSource in a WinForms application.
+    /// The DesktopWindowXamlSource is backed by a DesktopChildSiteBridge HWND that is a child of the WinForms Control.
+    /// The HWND tree looks like this:
+    /// * Top-level WinForms HWND
+    ///   * DesktopWindowXamlSourceControl HWND
+    ///     * DesktopChildSiteBridge HWND
+    ///   * Other WinForms control HWNDs
+    ///   * Other WinForms control HWNDs
+    /// </summary>
+    public partial class DesktopWindowXamlSourceControl : System.Windows.Forms.Control
+    {
+        public DesktopWindowXamlSourceControl()
+        {
+            InitializeComponent();
+        }
+
+        protected override void OnGotFocus(EventArgs e)
+        {
+            if (_desktopWindowXamlSource != null)
+            {
+                // The DesktopWindowXamlSourceControl is getting focus, let's redirect focus to the Xaml content by
+                // calling DesktopWindowXamlSource.NavigateFocus.
+                bool isShiftPressed = ((Form.ModifierKeys & Keys.Shift) != 0);
+                var reason = isShiftPressed ? Microsoft.UI.Xaml.Hosting.XamlSourceFocusNavigationReason.Last : Microsoft.UI.Xaml.Hosting.XamlSourceFocusNavigationReason.First;
+                var request = new XamlSourceFocusNavigationRequest(reason);
+                _desktopWindowXamlSource.NavigateFocus(request);
+            }
+        }
+
+        private void OnDesktopWindowXamlSourceTakeFocusRequested(object sender, DesktopWindowXamlSourceTakeFocusRequestedEventArgs e)
+        {
+            // The DesktopWindowXamlSource is requesting that the host take focus.
+            // This typically happens when the user is tabbing through the controls in the Xaml content and reaches the first or last control.
+            if (e.Request.Reason == XamlSourceFocusNavigationReason.First)
+            {
+                FocusNextFocusableWinFormsControl(this.Parent!, this, true /*forward*/);
+            }
+            else if (e.Request.Reason == XamlSourceFocusNavigationReason.Last)
+            {
+                FocusNextFocusableWinFormsControl(this.Parent!, this, false /*forward*/);
+            }
+        }
+
+        private void InitializeDesktopWindowXamlSource()
+        {
+            _desktopWindowXamlSource = new Microsoft.UI.Xaml.Hosting.DesktopWindowXamlSource();
+
+            _desktopWindowXamlSource.Initialize(new WindowId((ulong)this.Handle));
+
+            _desktopWindowXamlSource.TakeFocusRequested += 
+                new TypedEventHandler<DesktopWindowXamlSource, DesktopWindowXamlSourceTakeFocusRequestedEventArgs>(
+                    OnDesktopWindowXamlSourceTakeFocusRequested);
+
+            _desktopWindowXamlSource.SiteBridge.MoveAndResize(new Windows.Graphics.RectInt32(0, 0, this.Width, this.Height));
+
+            _frame = new Frame();
+            _desktopWindowXamlSource.Content = _frame;
+
+            _desktopWindowXamlSource.SystemBackdrop = new DesktopAcrylicBackdrop();
+
+            if (_content != null)
+            {
+                _frame.Content = _content;
+            }
+        }
+
+        protected override void OnResize(EventArgs e)
+        {
+            base.OnResize(e);
+            if (_desktopWindowXamlSource != null)
+            {
+                // Resize the DesktopChildSiteBridge HWND to match the size of the WinForms control, it's parent.
+                _desktopWindowXamlSource.SiteBridge.MoveAndResize(new Windows.Graphics.RectInt32(0, 0, this.Width, this.Height));
+            }
+        }
+
+        protected override void OnPaint(PaintEventArgs pe)
+        {
+            if (this.DesignMode)
+            {
+                base.OnPaint(pe);
+                pe.Graphics.FillRectangle(Brushes.LightGray, this.ClientRectangle);
+                pe.Graphics.DrawString("DesktopWindowXamlSourceControl", this.Font, Brushes.Black, 10, 10);
+            }
+            else if (_desktopWindowXamlSource == null)
+            {
+                InitializeDesktopWindowXamlSource();
+            }
+        }
+
+        /// <summary>
+        /// Sets the content of the DesktopWindowXamlSource.
+        /// </summary>
+        public FrameworkElement? Content
+        {
+            get
+            {
+                return _content;
+            }
+            set
+            {
+                _content = value;
+                if (_frame != null)
+                {
+                    _frame.Content = _content;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Call to move focus to the next focusable control in the parent.
+        /// </summary>
+        /// <param name="parent">Control or Form that contains the controls.</param>
+        /// <param name="start">Control we're starting with.</param>
+        /// <param name="forward">If true, focus is moving forward.  If not, backward.</param>
+        private static void FocusNextFocusableWinFormsControl(System.Windows.Forms.Control parent, System.Windows.Forms.Control start, bool forward)
+        {
+            // GetNextControl can return controls that aren't tab stops, so keep going until we find one that is.
+            System.Windows.Forms.Control? next = start;
+            do
+            {
+                next = parent.GetNextControl(next, forward);
+            }
+            while (next != null && next.TabStop == false);
+
+            if (next == null)
+            {
+                // Oops, we ran out of controls.  Get the first control in the parent.
+                next = parent.GetNextControl(null, forward);
+            }
+
+            if (next != null)
+            {
+                next.Focus();
+            }
+        }
+
+        private FrameworkElement? _content;
+        private Frame? _frame;
+        private DesktopWindowXamlSource? _desktopWindowXamlSource;
+    }
+}

Samples/Islands/cs-winforms-unpackaged/DesktopWindowXamlSourceControl.resx

@@ -0,0 +1,120 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+
+    Version 2.0
+
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+
+    Example:
+
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>