Merge pull request #2696 from cwensley/curtis/wpf-dialog-visible

Wpf: Setting Dialog.Visible=false after shown should not crash

src/Eto.Wpf/Forms/DialogHandler.cs

@@ -37,7 +37,7 @@ protected override AutomationPeer OnCreateAutomationPeer()
 			return new EtoWindowAutomationPeer(this);
 		}
 	}
-	
+
 	public class DialogHandler : WpfWindow<sw.Window, Dialog, Dialog.ICallback>, Dialog.IHandler
 	{
 		Button defaultButton;
@@ -64,7 +64,7 @@ public DialogHandler(sw.Window window)
 		protected override void Initialize()
 		{
 			base.Initialize();
-			
+
 			Resizable = false;
 			Minimizable = false;
 			Maximizable = false;
@@ -85,7 +85,7 @@ public void ShowModal()
 			ReloadButtons();
 
 			var owner = Widget.Owner;
-			
+
 			if (LocationSet)
 			{
 				Control.WindowStartupLocation = sw.WindowStartupLocation.Manual;
@@ -97,7 +97,7 @@ public void ShowModal()
 				parentWindowBounds = owner.Bounds;
 				Control.Loaded += HandleLoaded;
 			}
-			
+
 			// if the owner doesn't have focus, windows changes the owner's z-order after the dialog closes.
 			if (owner != null && !owner.HasFocus)
 				owner.Focus();
@@ -120,6 +120,13 @@ public void ShowModal()
 			ClearButtons();
 		}
 
+		public override void SetOwner(Window owner)
+		{
+			// Dialogs can not change owner after shown
+			if (!Widget.Loaded)
+				base.SetOwner(owner);
+		}
+
 		void Control_PreviewKeyDown(object sender, sw.Input.KeyEventArgs e)
 		{
 			if (e.Key == sw.Input.Key.Escape && AbortButton != null)

src/Eto.Wpf/Forms/WpfWindow.cs

@@ -1075,7 +1075,7 @@ public void SetOwnerFor(sw.Window child)
 			child.Owner = Control;
 		}
 
-		public void SetOwner(Window owner)
+		public virtual void SetOwner(Window owner)
 		{
 			if (owner == null)
 			{