InvalidOperationException - object is currently in use elsewhere - red cross

Question

I have a C# desktop application in which one thread that I create continously gets an image from a source(it\'s a digital camera actually) and puts it on a panel(panel.Image

Answer 1

Seems to me, that the same Camera object is used several times.

E.g. try to use a new buffer for each received frame. It seems to me, that while the picture box is drawing the new frame, your capture library fills that buffer again. Therefore on faster machines this might not be an issue, with slower machines it might be an issue.

I've programmed something similar once, after each received frame, we had to request to receive the next frame and set the NEW frame receive buffer in that request.

If you can not do that, copy the received frame from the camera first to a new buffer and append that buffer to a queue, or just use 2 alternating buffers and check for overruns. Either use myOutPutPanel.BeginInvoke to call the camera_ReceivedFrame method, or better have a thread running, which checks the queue, when it has a new entry it calls mnyOutPutPanel.BeginInvoke to invoke your method to set the new buffer as image on the panel.

Furthermore, once you received the buffer, use the Panel Invoke Method to invoke the setting of the image (guarantee that it runs in the window thread and not the thread from your capture library).

The example below can be called from any thread (capture library or other separate thread):

void camera_ReceivedFrame(object sender, StreamEventArgs e)
{
    if(myOutputPanel.InvokeRequired)
    {
        myOutPutPanel.BeginInvoke( 
            new Camera.ReceivedFrameEventHandler(camera_ReceivedFrame), 
            sender, 
            e);
    }
    else
    {
        myOutPutPanel.Image = e.Image;
    }
}