I think Popup will be the best option for you.
You can make a popup control and show on top of your main control.
Popup.IsOpen - property will work as Window.Show() - function
public static void Show(UIElement parent, string message)
{
Popup popupWindow = new Popup();
DockPanel dp = new DockPanel();
dp.Children.Add(new TextBlock() { Text = message });
Button btnOK = new Button { Content = "OK" };
btnOK.Click += delegate { popupWindow.IsOpen = false; };
dp.Children.Add(btnOK);
popupWindowwindow.PlacementTarget = parent;
popupWindowwindow.Placement = PlacementMode.Center;
popupWindowwindow.IsOpen = true;
}
Thanks
Derin