xamarin
Potential memory leak in UrhoSurface WPF binding
I have a simple test app (see https://github.com/jonaspegerfalk/UrhoSharp.TestMemoryLeak) that switches between two user controls, one empty and one with a UrhoSurface WPF element as below. No more Urho magic is initiated in the test app.
<UserControl x:Class="UrhoTestApp.UserControl2"
...
>
<Grid x:Name="Grid1">
<TextBlock>User control 2</TextBlock>
<wpf:UrhoSurface x:Name="Urho1">
</wpf:UrhoSurface>
</Grid>
</UserControl>
The user can switch between the two user controls and a new instance of the user controls is created when the user switches to it. The previously visible user control is then removed from the visual tree.
The potential memory leak
This works perfectly fine with the empty user control everything is cleared up when switching away from it. But the second one, with the UrhoSurface object, does not work correctly. The UrhoSurface object is never garbage collected and after a while there will be lots of UrhoSurface objects in memory.
Below is a dependency graph from ANTS memory profiler and it seems like there is something in the input event handling that keeps a reference to the UrhoSurface preventing it from being garbage collected.
Here is the image as a PDF, which is a bit easier to read :-)