I’ve had similar problem and found a solution:
public static class WindowsServices
{
const int WS_EX_TRANSPARENT = 0x00000020;
const int GWL_EXSTYLE = (-20);
[DllImport("user32.dll")]
static extern int GetWindowLong(IntPtr hwnd, int index);
[DllImport("user32.dll")]
static extern int SetWindowLong(IntPtr hwnd, int index, int newStyle);
public static void SetWindowExTransparent(IntPtr hwnd)
{
var extendedStyle = GetWindowLong(hwnd, GWL_EXSTYLE);
SetWindowLong(hwnd, GWL_EXSTYLE, extendedStyle | WS_EX_TRANSPARENT);
}
}
for your window set:
WindowStyle = None
Topmost = true
AllowsTransparency = true
in code behind for the window add:
protected override void OnSourceInitialized(EventArgs e)
{
base.OnSourceInitialized(e);
var hwnd = new WindowInteropHelper(this).Handle;
WindowsServices.SetWindowExTransparent(hwnd);
}
and voila – click-through window! See original answer in: http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/a3cb7db6-5014-430f-a5c2-c9746b077d4f