Use XAML Islands to host a UWP XAML control in a C# WPF app

Artikel
08/21/2024

Important

This topic uses or mentions types from the CommunityToolkit/Microsoft.Toolkit.Win32 GitHub repo. For important info about XAML Islands support, please see the XAML Islands Notice in that repo.

This topic shows how to build a C# Windows Presentation Foundation (WPF) app (targeting .NET Core 3.1) that uses XAML Islands to host a Universal Windows Platform (UWP) XAML control (that is, a first-party control provided by the Windows SDK). We show how to do that in two ways:

We show how to host UWP InkCanvas and InkToolbar controls by using wrapped controls (available in the Windows Community Toolkit). Wrapped controls wrap the interface and functionality of a small set of useful UWP XAML controls. You can add a wrapped control directly to the design surface of your WPF or Windows Forms project, and then use it in the designer like any other WPF or Windows Forms control.
We also show how to host a UWP CalendarView control by using the WindowsXamlHost control (available in the Windows Community Toolkit). Because only a small set of UWP XAML controls are available as wrapped controls, you can use WindowsXamlHost to host any UWP XAML control.

The process for hosting a UWP XAML control in a WPF app is similar for a Windows Forms app.

Important

Using XAML Islands (wrapped controls or WindowsXamlHost) to host UWP XAML controls is supported only in apps that target .NET Core 3.x. XAML Islands are not supported in apps that target .NET, or in apps that target any version of the .NET Framework.

Recommended components

To host a UWP XAML control in a WPF or Windows Forms app, we recommend that you have the following components in your solution. This topic provides instructions for creating each of these components:

The project and source code for your WPF or Windows Forms app.
A UWP project that defines a root Application class that derives from XamlApplication. The Microsoft.Toolkit.Win32.UI.XamlHost.XamlApplication class is available in the Windows Community Toolkit). We recommended that you define your XamlApplication-derived Application class a separate UWP app project that's part of your WPF or Windows Forms Visual Studio solution.

Note

Making a XamlApplication-derived object available to your WPF or Windows Forms project isn't actually required in order to host a first-party UWP XAML control. But it is necessary in order to discover, load, and host custom UWP XAML controls. So—to support the full range of XAML Island scenarios—we recommend that you always define a XamlApplication-derived object in any solution in which you use XAML Islands.

Note

Your solution can contain only one project that defines a XamlApplication-derived object. That one project must reference any other libraries and projects that host UWP XAML controls via XAML Islands.

Create a WPF project

You can follow these instructions to create a new WPF project, and configure it to host XAML Islands. If you have an existing WPF project, then you can adapt these steps and code examples for your project.

If you haven't done so already, then install the latest version of .NET Core 3.1.
In Visual Studio, create a new C# project from the WPF Application project template. Set the Project name to MyWPFApp so that you won't need to edit any of the steps or source code in this topic. Set the Framework to .NET Core 3.1*, and click Create.

Important

Be sure not to use the WPF App (.NET Framework) project template.

Configure your WPF project

These steps enable package references:
1. In Visual Studio, click Tools > NuGet Package Manager > Package Manager Settings.
2. On the right, find the Package Management > Default package management format setting, and set it to PackageReference.
Use these steps to install the Microsoft.Toolkit.Wpf.UI.Controls NuGet Package:
1. Right-click the MyWPFApp project node in Solution Explorer, and choose Manage NuGet Packages....
2. On the Browse tab, type or paste Microsoft.Toolkit.Wpf.UI.Controls into the search box. Select the latest stable version, and click Install. That package provides everything you need to use the wrapped UWP XAML controls for WPF (including InkCanvas, InkToolbar, and the WindowsXamlHost control).
Note

For a Windows Forms app, reference the Microsoft.Toolkit.Forms.UI.Controls package instead.
Most XAML Islands scenarios aren't supported in projects that target Any CPU. So to target a specific architecture (such as x86 or x64), do the following:
1. Right-click the solution node (not the project node) in Solution Explorer, and choose Properties.
2. Select Configuration Properties on the left.
3. Click the Configuration Manager... button.
4. Under Active solution platform, select New.
5. In the New Solution Platform dialog, select x64 or x86, and press OK.
6. Close the open dialog boxes.

Define a XamlApplication class in a new UWP project

In this section we'll be adding a UWP project to the solution, and revising the default App class in that project to derive from the Microsoft.Toolkit.Win32.UI.XamlHost.XamlApplication class provided by the Windows Community Toolkit. That class supports the IXamlMetadataProvider interface, which enables your app to discover and load metadata for custom UWP XAML controls in assemblies in the current directory of your application at run time. That class also initializes the UWP XAML framework for the current thread.

In Solution Explorer, right-click the solution node, and select Add > New Project....
Select the C# Blank App (Universal Windows) project template. Set the Project name to MyUWPApp so that you won't need to edit any of the steps or source code in this topic. Set the Target version and Minimum version to either Windows 10, version 1903 (Build 18362) or later.

Note

Be sure not to create MyUWPApp in a subfolder of MyWPFApp. If you do that, then MyWPFApp will try to build the UWP XAML markup as if it were WPF XAML.
In MyUWPApp, install the Microsoft.Toolkit.Win32.UI.XamlApplication NuGet package (latest stable version). The process for installng a NuGet package was described in the previous section.

In MyUWPApp, open the App.xaml file, and replace its contents with the following XAML:

<xaml:XamlApplication
    x:Class="MyUWPApp.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:xaml="using:Microsoft.Toolkit.Win32.UI.XamlHost"
    xmlns:local="using:MyUWPApp">
</xaml:XamlApplication>

Similarly, open App.xaml.cs, and replace its contents with the following code:

namespace MyUWPApp
{
    public sealed partial class App : Microsoft.Toolkit.Win32.UI.XamlHost.XamlApplication
    {
        public App()
        {
            this.Initialize();
        }
    }
}

Delete the MainPage.xaml and MainPage.xaml.cs files.
Build the MyUWPApp project.

In MyWPFApp, add a reference to the MyUWPApp project

Specify the compatible framework version in MyWPFApp's project file like this:
1. In Solution Explorer, click the MyWPFApp project node to open the project file in the editor.
2. Inside the first PropertyGroup element, add the following child element. Change the 19041 portion of the value as necessary to match the target and minimum OS build of the MyWPFApp project.
```
<AssetTargetFallback>uap10.0.19041</AssetTargetFallback>
```
In Solution Explorer, right-click MyWPFApp > Dependencies, choose Add Project Reference..., and add a reference to the MyUWPApp project.

Instantiate the XamlApplication object in the entry point of MyWPFApp

Next, add code to the entry point of MyWPFApp to create an instance of the App class that you just defined in MyUWPApp (the class that derives from XamlApplication).

Right-click the MyWPFApp project node, select Add > New Item..., and then select Class. Set Name to Program.cs, and click Add.

Replace the contents of Program.cs with the following XAML (and then save the file and build the MyWPFApp project):

namespace MyWPFApp
{
    public class Program
    {
        [System.STAThreadAttribute()]
        public static void Main()
        {
            using (new MyUWPApp.App())
            {
                var app = new MyWPFApp.App();
                app.InitializeComponent();
                app.Run();
            }
        }
    }
}

Right-click the MyWPFApp project node, and choose Properties.
In Application > General, click the Startup object drop-down, and choose MyWPFApp.Program (which is the fully-qualified name of the Program class that you just added). If you don't see it, then try closing and reopening Visual Studio.

Note

By default, a WPF project defines a Main entry point function in a generated code file that isn't intended to be modified. The step above changes the entry point for your project to the Main method of the new Program class, which enables you to add code that runs as early in the startup process of the app as possible.
Save your changes to the project properties.

Use wrapped controls to host an InkCanvas and InkToolbar

Now that you've configured your project to use UWP XAML Islands, you're ready to add the InkCanvas and InkToolbar wrapped UWP XAML controls to the app.

In MyWPFApp, open the MainWindow.xaml file.
In the Window element near the top of the XAML file, add the following attribute. This attribute references the XAML namespace for the InkCanvas and InkToolbar wrapped UWP XAML controls, and maps it to the controls XML namespace.
```
xmlns:controls="clr-namespace:Microsoft.Toolkit.Wpf.UI.Controls;assembly=Microsoft.Toolkit.Wpf.UI.Controls"
```

Still in MainWindow.xaml, edit the existing Grid element so that it looks like the XAML below. This XAML adds to the Grid an InkCanvas and an InkToolbar control (prefixed by the controls XML namespace that you defined in the previous step).

<Grid Margin="10,50,10,10">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>
    <controls:InkToolbar x:Name="myInkToolbar" TargetInkCanvas="{x:Reference myInkCanvas}" Grid.Row="0" Width="300"
        Height="50" Margin="10,10,10,10" HorizontalAlignment="Left" VerticalAlignment="Top" />
    <controls:InkCanvas x:Name="myInkCanvas" Grid.Row="1" HorizontalAlignment="Left" Width="600" Height="400"
        Margin="10,10,10,10" VerticalAlignment="Top" />
</Grid>

Note

You can also add these and other wrapped controls to the Window by dragging them to the designer from the Windows Community Toolkit section of the Toolbox.

Save MainWindow.xaml.

If you have a device that supports a digital pen (such as a Surface), and you're following along on a physical machine, then you could now build and run the app, and draw digital ink on the screen with the pen. But if you try to write with your mouse, then nothing will happen, because by default InkCanvas is enabled only for digital pens. Here's how to enable InkCanvas for the mouse.
Still in MyWPFApp, open MainWindow.xaml.cs.
Add the following namespace directive to the top of the file:
```
using Microsoft.Toolkit.Win32.UI.Controls.Interop.WinRT;
```
Locate the MainWindow constructor. Immediately after the call to InitializeComponent, add the following line of code:
```
myInkCanvas.InkPresenter.InputDeviceTypes = CoreInputDeviceTypes.Mouse | CoreInputDeviceTypes.Pen;
```
You can use the InkPresenter object to customize the default inking experience. The code above uses the InputDeviceTypes property to enable mouse as well as pen input.
Save, build, and run. If you're using a computer with a mouse, then confirm that you can draw something in the ink canvas space with the mouse.

Host a CalendarView by using the host control

In this section, we'll use the WindowsXamlHost control to add a CalendarView to the app.

Note

The WindowsXamlHost control is provided by the Microsoft.Toolkit.Wpf.UI.XamlHost package. That package is included with the Microsoft.Toolkit.Wpf.UI.Controls package that you installed earlier.

In Solution Explorer, in MyWPFApp, open the MainWindow.xaml file.
In the Window element near the top of the XAML file, add the following attribute. This attribute references the XAML namespace for the WindowsXamlHost control, and maps it to the xamlhost XML namespace.
```
xmlns:xamlhost="clr-namespace:Microsoft.Toolkit.Wpf.UI.XamlHost;assembly=Microsoft.Toolkit.Wpf.UI.XamlHost"
```
Still in MainWindow.xaml, edit the existing Grid element so that it looks like the XAML below. This XAML adds to the Grid a WindowsXamlHost control (prefixed by the xamlhost XML namespace that you defined in the previous step). To host a UWP CalendarView control, this XAML sets the InitialTypeName property to the fully-qualified name of the control. The XAML also defines an event handler for the ChildChanged event, which is raised when the hosted control has been rendered.
```
<Grid Margin="10,50,10,10">
    <xamlhost:WindowsXamlHost x:Name="myCalendar" InitialTypeName="Windows.UI.Xaml.Controls.CalendarView"
          Margin="10,10,10,10" Width="600" Height="300" ChildChanged="MyCalendar_ChildChanged" />
</Grid>
```
Save MainWindow.xaml, and open MainWindow.xaml.cs.
Delete this line of code, which we added in the previous section: myInkCanvas.InkPresenter.InputDeviceTypes = CoreInputDeviceTypes.Mouse | CoreInputDeviceTypes.Pen;.
Add the following namespace directive to the top of the file:
```
using Microsoft.Toolkit.Wpf.UI.XamlHost;
```

Add the following ChildChanged event handler method to the MainWindow class. When the host control has been rendered, this event handler runs and creates a simple event handler for the SelectedDatesChanged event of the calendar control.

private void MyCalendar_ChildChanged(object sender, EventArgs e)
{
    WindowsXamlHost windowsXamlHost = (WindowsXamlHost)sender;

    var calendarView =
        (Windows.UI.Xaml.Controls.CalendarView)windowsXamlHost.Child;

    if (calendarView != null)
    {
        calendarView.SelectedDatesChanged += (obj, args) =>
        {
            if (args.AddedDates.Count > 0)
            {
                MessageBox.Show("The user selected a new date: " +
                    args.AddedDates[0].DateTime.ToString());
            }
        };
    }
}

Save, build, and run. Confirm that the calendar control is shown in the window, and that a message box is displayed when you select a date.

Package the app

You can optionally package your WPF app in an MSIX package for deployment. MSIX is the modern and reliable app packaging technology for Windows.

The following instructions show you how to package all the components in the solution into an MSIX package by using the Windows Application Packaging Project in Visual Studio (see Set up your desktop application for MSIX packaging in Visual Studio). These steps are necessary only if you want to package the WPF app in an MSIX package.

Note

If you choose not to package your application in an MSIX package for deployment, then computers that run your app must have the Visual C++ Runtime installed.

Add a new project to your solution created from the Windows Application Packaging Project project template. As you create the project, select the same Target version and Minimum version as you selected for the UWP project.
In the packaging project, right-click the Dependencies node, and choose Add Project Reference.... In the list of projects, select MyWPFApp, and click OK.

Note

If you want to publish your app in the Microsoft Store, then you also have to add a reference to the UWP project in the packaging project.
If you followed the steps up to this point, then all of the projects in your solution will target the same specific platform (x86 or x64). And that's necessary in order to build the WPF app into an MSIX package using the Windows Application Packaging Project. To confirm that, you can follow these steps:
1. Right-click the solution node (not the project node) in Solution Explorer, and choose Properties.
2. Select Configuration Properties on the left.
3. Click the Configuration Manager... button.
4. Confirm that all of the listed projects have the same value under Platform: either x86 or x64.
Right-click the project node for the packaging project that you just added, and click Set as Startup project.
Build and run the packaging project. Confirm that the WPF app runs, and that the UWP control(s) display as expected.
For info about distributing/deploying the package, see Manage your MSIX deployment.

Dela via

Use XAML Islands to host a UWP XAML control in a C# WPF app

Recommended components

Create a WPF project

Configure your WPF project

Define a XamlApplication class in a new UWP project

In MyWPFApp, add a reference to the MyUWPApp project

Instantiate the XamlApplication object in the entry point of MyWPFApp

Use wrapped controls to host an InkCanvas and InkToolbar

Host a CalendarView by using the host control

Package the app

Ytterligare resurser

Dela via

Use XAML Islands to host a UWP XAML control in a C# WPF app

Recommended components

Create a WPF project

Configure your WPF project

Define a XamlApplication class in a new UWP project

In MyWPFApp, add a reference to the MyUWPApp project

Instantiate the XamlApplication object in the entry point of MyWPFApp

Use wrapped controls to host an InkCanvas and InkToolbar

Host a CalendarView by using the host control

Package the app

Related topics

Ytterligare resurser