Programming WPF, 2nd Edition

Hosting a WPF Control in Windows Forms

Hosting a WPF control in Windows Forms is much the same as hosting a Windows Forms Control in WPF: we need a host. In WPF, we needed a host that was an element that could fit into WPF, but that also provided an HWND for use by the Windows Forms control. In Windows Forms, we need a Windows Forms Control-derived class so that it can fit into a container's Controls collection. For that, we have the ElementHost class, also from the System.Windows.Forms.Integration namespace and the WindowsFormsIntegration assembly.

The ElementHost class derives from ContainerControl to enable hosting other Windows Forms controls. The element host knows about HWNDs, how to size and paint itself, and how to handle keystrokes and focus. As an example, let's say we've got a form all laid out in the Windows Forms Designer, as shown in Figure B-5.

Figure B-5. A Windows Forms form with space for a WPF button

In Figure B-5, we've got a form with two group boxes: one with a Windows Forms button laid out on the left using the Windows Forms Designer and one blank on the right, all ready for a WPF button to be added at runtime, which is what the code in Example B-5 does.

Example B-5. Creating a WPF button in a Windows Forms application

// Form1.cs ... using System.Windows.Forms.Integration; public partial class Form1 : Form { public Form1( ) { InitializeComponent( ); // group boxes ...