WPF - Update "System.Windows.Controls.Image" from another thread

Question

I get this exception on that code. How to fix it?

Excepton:

The calling thread cannot access this object because a different thread owns it.

Code:

    void CamProc_NewTargetPosition(IntPoint Center, System.Drawing.Bitmap image)
    {
        IntPtr hBitMap = image.GetHbitmap();
        BitmapSource bmaps = Imaging.CreateBitmapSourceFromHBitmap(hBitMap, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());

        Dispatcher.BeginInvoke((Action)(() =>
        {
            labelX.Content = String.Format("X: {0}", Center.X); //OK Working
            labelY.Content = String.Format("Y: {0}", Center.Y); //OK Working
            pictureBoxMain.Source = bmaps; // THERE IS EXCEPTON
        }), DispatcherPriority.Render, null);

    }

pictureBoxMain is System.Windows.Controls.Image.

Kent Boogaart · Accepted Answer · 2011-09-28 00:35:43Z

7

You can freeze the BitmapSource so that it can be accessed from any thread:

void CamProc_NewTargetPosition(IntPoint Center, System.Drawing.Bitmap image)
    {
        IntPtr hBitMap = image.GetHbitmap();
        BitmapSource bmaps = Imaging.CreateBitmapSourceFromHBitmap(hBitMap, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
        bmaps.Freeze();

        Dispatcher.BeginInvoke((Action)(() =>
        {
            labelX.Content = String.Format("X: {0}", Center.X);
            labelY.Content = String.Format("Y: {0}", Center.Y);
            pictureBoxMain.Source = bmaps;
        }), DispatcherPriority.Render, null);

    }

edited Sep 28, 2011 at 0:35

user142162

answered Jan 13, 2011 at 23:22

Kent Boogaart

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Community · Accepted Answer · 2017-05-23 11:53:55Z

2

You could Freeze the image, as suggested in another thread, which gets rid of the threading restriction but makes the image immutable.

WPF/BackgroundWorker and BitmapSource problem

edited May 23, 2017 at 11:53

CommunityBot

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answered Jan 13, 2011 at 23:25

James

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