Calc: Step 6.1: Prepare for DrawingIsland - Add WpfIslandHost.cs and DisplayAreaBorder element

Author: JesseCol

Samples/Islands/DrawingIsland/CalculatorDemo/CalculatorDemo.csproj

@@ -113,6 +113,7 @@
       <DependentUpon>Settings.settings</DependentUpon>
       <DesignTimeSharedInput>True</DesignTimeSharedInput>
     </Compile>
+    <Compile Include="WpfIslandHost.cs" />
     <EmbeddedResource Include="Properties\Resources.resx">
       <Generator>ResXFileCodeGenerator</Generator>
       <LastGenOutput>Resources.Designer.cs</LastGenOutput>

Samples/Islands/DrawingIsland/CalculatorDemo/MainWindow.xaml

@@ -137,7 +137,9 @@
                 Also, make the TextBox borders a little less harsh.
                 -->
                 <local:MyTextBox Grid.ColumnSpan="9" x:Name="DisplayBox" Height="30" Margin="5" FontSize="20" BorderBrush="LightGray"/>
-                <local:MyTextBox Grid.Row="1" Grid.ColumnSpan="3" Grid.RowSpan="5" Margin="5" x:Name="PaperBox" BorderBrush="LightGray"/>
+                <Border Name="DisplayAreaBorder" Grid.Row="1" Grid.ColumnSpan="3" Grid.RowSpan="5" Margin="5">
+                    <local:MyTextBox x:Name="PaperBox" BorderBrush="LightGray"/>
+                </Border>
             </Grid>
 
         </DockPanel>

Samples/Islands/DrawingIsland/CalculatorDemo/WpfIslandHost.cs

@@ -0,0 +1,34 @@
+using Microsoft.UI.Composition;
+using Microsoft.UI.Content;
+using System.Runtime.InteropServices;
+using System.Windows.Interop;
+
+namespace CalculatorDemo
+{
+    internal class WpfIslandHost : HwndHost
+    {
+        public WpfIslandHost(Compositor compositor)
+        {
+            _compositor = compositor;
+        }
+
+        public DesktopChildSiteBridge DesktopChildSiteBridge { get; private set; }
+
+        protected override HandleRef BuildWindowCore(HandleRef hwndParent)
+        {
+            DesktopChildSiteBridge = Microsoft.UI.Content.DesktopChildSiteBridge.Create(
+                _compositor,
+                new Microsoft.UI.WindowId((ulong)hwndParent.Handle));
+
+            return new HandleRef(null, (nint)DesktopChildSiteBridge.WindowId.Value);
+        }
+
+        protected override void DestroyWindowCore(HandleRef hwnd)
+        {
+            DesktopChildSiteBridge.Dispose();
+            DesktopChildSiteBridge = null;
+        }
+
+        Microsoft.UI.Composition.Compositor _compositor;
+    }
+}