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dirtylarry
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accessing wpf Colors in a different thread?

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i have a program that needs to change the color of a rectangle. but i'm using threads. here's what i have

mySolidColorBrush.Dispatcher.Invoke(DispatcherPriority.Send, new FillBoxColor(fillBoxColor), Colors.Green;

delegate void FillBoxColor(Colors x);
        void fillBoxColor(Colors x)
        {
            mySolidColorBrush.Color = x;
            rctIsConnected.Fill = mySolidColorBrush;
        }


i always get the cannot convert system.windows.media.color to system.windows.media.colors error. any ideas?

wpf colors
  • asked one year ago
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last answered one year ago

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I think that what you want is :

mySolidColorBrush.Dispatcher.Invoke(DispatcherPriority.Send, new FillBoxColor(fillBoxColor), Colors.Green);

delegate void FillBoxColor(object x);  // not Colors
void fillBoxColor(object x) // ditto
{
    mySolidColorBrush.Color = (Color)x; // need a cast here
    rctIsConnected.Fill = mySolidColorBrush;
}

  • answered one year ago by:

    vulpes
    17279
(x)
dirtylarry
237

thanks for the reply vulpes, but i tried that and i'm back to the error that the thread can't access it because it's not the same thread

(x)
vulpes
17279

Well, that's a different error altogether but it makes no sense because, of course, the rationale for using Dispatcher.Invoke in the first place is to marshal UI changes back to the UI thread. Do you still get the error if you use BeginInvoke rather than Invoke?

(x)
dirtylarry
237

when i try begininvoke, i get no errors, but it seems to just skip over the color change. tried to add a breakpoint, and it's definately running the line, but it's not changing the color.

(x)
vulpes
17279

It's difficult to know what else to suggest but I'd try reducing the DispatcherPriority from Send to Normal in case that's upsetting matters.

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