How to show a preview of screen saver inside WPF window

Question

I want to be able to show a preview of a screen saver inside WPF window. (using a container or control or ...) I know that Windows itself passes "/p" argument to the screen saver to get a preview. But how can I show that preview inside my WPF application? Should I get a handle of it and change its parent to my container o control? How?

Answer 1

You need to use Windows.Forms interop, because screen savers expect windows handles (HWND) and in WPF, only top-level windows have them.

MainWindow.xaml

<Window x:Class="So18547663WpfScreenSaverPreview.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:forms="clr-namespace:System.Windows.Forms;assembly=System.Windows.Forms"
        Title="Screen Saver Preview" Height="350" Width="525"
        Loaded="MainWindow_OnLoaded" Closed="MainWindow_OnClosed"
        SizeToContent="WidthAndHeight">
    <StackPanel Orientation="Vertical" Margin="8">
        <TextBlock Text="Preview"/>
        <WindowsFormsHost x:Name="host" Width="320" Height="240">
            <forms:Control Width="320" Height="240"/>
        </WindowsFormsHost>
    </StackPanel>
</Window>

MainWindow.xaml.cs

using System;
using System.Diagnostics;
using System.Windows;

namespace So18547663WpfScreenSaverPreview
{
    public partial class MainWindow
    {
        private Process saver;

        public MainWindow ()
        {
            InitializeComponent();
        }

        private void MainWindow_OnLoaded (object sender, RoutedEventArgs e)
        {
            saver = Process.Start(new ProcessStartInfo {
                FileName = "Bubbles.scr",
                Arguments = "/p " + host.Child.Handle,
                UseShellExecute = false,
            });
        }

        private void MainWindow_OnClosed (object sender, EventArgs e)
        {
            // Optional. Screen savers should close themselves
            // when the parent window is destroyed.
            saver.Kill();
        }
    }
}

Assembly references

• WindowsFormsIntegration
• System.Windows.Forms

Related links

• Walkthrough: Hosting a Windows Forms Control in WPF
• Creating a Screen Saver with C# (describes command line arguments)