Render WPF control on top of WindowsFormsHost - wpf

Question

I know that default WPF behavior is to render WPF controls and then on top render WinForms, but are there any way to render WPF on top of WindowsFormsHost?
Edit: I have found a temp hack as well. When wpf control overlaps WindowsFormsHost, I change the size of the WindowsFormsHost (This only works when you have rectangular object which overlaps, doesn't work for other shapes.)

Answer 1

Late to the party, I know, but I recently came across this issue using a WebBrowser control.
The final fix was to create a screenshot of the web browser whenever I hosted a modal dialog over the top. Since this was a little fiddly, I turned it into a Github project, hopefully this helps a little -
https://github.com/chris84948/AirspaceFixer
(It's on Nuget too, under AirspaceFixer)
Once you have the project all you need to do is this
xmlns:asf="clr-namespace:AirspaceFixer;assembly=AirspaceFixer"
<asf:AirspacePanel FixAirspace="{Binding FixAirspace}">
<WebBrowser x:Name="Browser" />
</asf:AirspacePanel>
Where FixAirspace is the dependency property that switches from the "real" view of the content, to the screenshot or "fake" view.

Answer 2

This "airspace" issue is suppose to be fixed in WPF vNext. There are a couple solutions out there, such as here, here, and here.
One way to do this is to host the WPF content in a transparent Popup or Window, which overlays the Interop content.

Answer 3

Try this on for size:
<hacks:AirspaceOverlay>
<hacks:AirspaceOverlay.OverlayChild>
<Canvas ToolTip = "A tooltip over a DirectX surface" Background="#01000000" Name="Overlay" />
</hacks:AirspaceOverlay.OverlayChild>
<controls:OpenGLControlWrappingWindowsFormsHost />
</hacks:AirspaceOverlay>
// Adapted from http://blogs.msdn.com/b/pantal/archive/2007/07/31/managed-directx-interop-with-wpf-part-2.aspx & http://www.4mghc.com/topics/69774/1/in-wpf-how-can-you-draw-a-line-over-a-windowsformshost
public class AirspaceOverlay : Decorator
{
private readonly Window _transparentInputWindow;
private Window _parentWindow;
public AirspaceOverlay()
{
_transparentInputWindow = CreateTransparentWindow();
_transparentInputWindow.PreviewMouseDown += TransparentInputWindow_PreviewMouseDown;
}
public object OverlayChild
{
get { return _transparentInputWindow.Content; }
set { _transparentInputWindow.Content = value; }
}
private static Window CreateTransparentWindow()
{
var transparentInputWindow = new Window();
//Make the window itself transparent, with no style.
transparentInputWindow.Background = Brushes.Transparent;
transparentInputWindow.AllowsTransparency = true;
transparentInputWindow.WindowStyle = WindowStyle.None;
//Hide from taskbar until it becomes a child
transparentInputWindow.ShowInTaskbar = false;
//HACK: This window and it's child controls should never have focus, as window styling of an invisible window
//will confuse user.
transparentInputWindow.Focusable = false;
return transparentInputWindow;
}
void TransparentInputWindow_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
_parentWindow.Focus();
}
protected override void OnRenderSizeChanged(SizeChangedInfo sizeInfo)
{
base.OnRenderSizeChanged(sizeInfo);
UpdateOverlaySize();
}
protected override void OnRender(DrawingContext drawingContext)
{
base.OnRender(drawingContext);
if (_transparentInputWindow.Visibility != Visibility.Visible)
{
UpdateOverlaySize();
_transparentInputWindow.Show();
_parentWindow = GetParentWindow(this);
_transparentInputWindow.Owner = _parentWindow;
_parentWindow.LocationChanged += ParentWindow_LocationChanged;
_parentWindow.SizeChanged += ParentWindow_SizeChanged;
}
}
private static Window GetParentWindow(DependencyObject o)
{
var parent = VisualTreeHelper.GetParent(o);
if (parent != null)
return GetParentWindow(parent);
var fe = o as FrameworkElement;
if (fe is Window)
return fe as Window;
if (fe != null && fe.Parent != null)
return GetParentWindow(fe.Parent);
throw new ApplicationException("A window parent could not be found for " + o);
}
private void ParentWindow_LocationChanged(object sender, EventArgs e)
{
UpdateOverlaySize();
}
private void ParentWindow_SizeChanged(object sender, SizeChangedEventArgs e)
{
UpdateOverlaySize();
}
private void UpdateOverlaySize()
{
var hostTopLeft = PointToScreen(new Point(0, 0));
_transparentInputWindow.Left = hostTopLeft.X;
_transparentInputWindow.Top = hostTopLeft.Y;
_transparentInputWindow.Width = ActualWidth;
_transparentInputWindow.Height = ActualHeight;
}
}

Answer 4

Here's a link to the best answer I've seen on this subject so far:
Can I overlay a WPF window on top of another?

Answer 5

If anyone finds themselves unsatisfied with the hacks, setting the Visibility of the WindowsFormsHost to Collapsed or Hidden is always an option.

Answer 6

I came across this issue while trying to create a MDI style interface hosting WinForms controls while porting a win forms app to WPF.
I managed to solve it by doing something like this:
WindowsFormsHost -> ElementHost -> WindowsFormsHost -> my win forms controls.
Its super ugly, but it creates windows layers for the WPF content to be under the WinForms content.