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C# -> F# translation problem
f#c#

Hello there,

I have a simple simple question regarding C# -> F# "translation".
I can seem to find a way to implement the last 2 lines of the C# snippet below.
Can someone point me in the right direction, please?

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void OnDrawingAreaExposed (object o, ExposeEventArgs args)
{
    DrawingArea area = (DrawingArea) o;
    Cairo.Context context = Gdk.CairoHelper.Create (area.GdkWindow);
 
    // Perform some drawing
 
    ((IDisposable) gr.Target).Dispose ();                               
    ((IDisposable) context).Dispose ();
}
.

Hi,
if you're having troubles with the casting to an interface type, then you can use this:

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(gr.Target :> IDisposable).Dispose()
(context :> IDisposable).Dispose()

F# makes a distinction between upcast (:>), which is a cast that cannot fail and a downcast (:?>), which ma fail (e.g. casting "System.Object" to "System.Random"). Anyway, there is also a nicer way for disposing resources:

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use context = Gdk.CairoHelper.Create(...)
// will be disposed automatically at the end of the method (and wrapped in a "try ... finally" block)
By on 11/22/2008 4:08 AM ()

Hi Tomas,

Thanks a lot, both suggestions worked just fine. I especially appreciate the second one as it really makes the code much cleaner.

Cheers,
Piotr

By on 11/22/2008 2:49 PM ()

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