Updating bitmapSource - copying one to another

Question

This is my exception

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

my function get results from a calculation and I want to update an already opened window..

 public override void UpdateResult(BaseMetricResults result)
        {
            var newResults = result as MetricUniformityResults;
            if (newResults == null)
            {
                return;
            }
            DispatcherHelper.UIDispatcher.Invoke(() =>
                {             
                    TopToBottomGraph.CrossSectionPoints.Clear();
                    foreach (var point in newResults.TopToBottomGraph.CrossSectionPoints)
                    {
                        TopToBottomGraph.CrossSectionPoints.Add(point);
                    }

                    newResults.JetMap.Freeze(); //exception here
                    byte[] arr = new byte[(int) (newResults.JetMap.Width*newResults.JetMap.Height*3)];
                    newResults.JetMap.CopyPixels(arr, (int) (newResults.JetMap.Width*3), 0);
                    JetMap = BitmapSource.Create((int) newResults.JetMap.Width, (int) newResults.JetMap.Height, 96, 96,
                                                 PixelFormats.Rgb24, BitmapPalettes.WebPalette, arr,
                                                 (int) (newResults.JetMap.Width*3));
                });
        }

This is my last attempt I'm not sure if I have to freeze the bitmapsource or not...
Anyway newResults.JetMap is BitmapSource, and I have a property named JetMap which is the new BitmapSource, how can I update the old image with the new one?

possible duplicate of [The calling thread cannot access this object because a different thread owns it](http://stackoverflow.com/questions/9732709/the-calling-thread-cannot-access-this-object-because-a-different-thread-owns-it) — Peter Duniho, Jan 22 '15 at 20:05
If you search SO for the error message you're getting, you will get some 400 possible answers, all of which offer much the same guidance: use `Dispatcher.Invoke()`. If your scenario calls for something different, you need to provide a question with enough detail, including [a complete code example](https://stackoverflow.com/help/mcve) and a clear, precise description of why it calls for something different. — Peter Duniho, Jan 22 '15 at 20:06
@PeterDuniho I think that you are wrong, I was just misusing function freeze(), as you can see it was solved. — Gilad, Jan 25 '15 at 09:49

score 1 · Answer 1 · answered Jan 22 '15 at 17:37

Your DispatcherHelper.UIDispatcher.Invoke method will execute on the UI thread. My best guess is that the newResults.JetMap bitmap was created on a different thread which is preventing you from modifying it. At the same time, you can't create the JetMap bitmap that you want to show on a thread other than the UI thread. So without more context, the best suggestion would be to ensure that the newResults.JetMap bitmap is also created in the main UI thread.

Amit Raz · Accepted Answer · 2015-01-25T08:27:24.757

1

You need to call Jetmap.Freeze(); right after you create it and not inside the dispatcher, once its its frozen you can set it inside the dispatcher and you wont get an exception

edited Jan 25 '15 at 08:27

answered Jan 22 '15 at 20:32

Amit Raz

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Tried. Still not wotking the execption will. Move to the line – Gilad Jan 22 '15 at 20:43
Maybe i should switch to writeablebitmap? Or allocate the bitmapsourceimage in the ui thread? – Gilad Jan 22 '15 at 20:44

Updating bitmapSource - copying one to another

2 Answers2