Question

Using the following code, we got the error ‘Object is currently in use elsewhere’

private void CaptureDone(System.Drawing.Bitmap e)
        {
            try
            {
                this.pictureBox.Image = e;
                 if (isSending)
                    ThreadPool.QueueUserWorkItem(new WaitCallback(SendVideoBuffer), pictureBox.Image);
            }
            catch (Exception) { }
        }

     void SendVideoBuffer(object bufferIn)
            {
    TcpClient tcp = new TcpClient(ConfigurationSettings.AppSettings[0].ToString(), 6000);
                           NetworkStream ns = tcp.GetStream();
                           if (ns != null)
                           {
                               System.Drawing.Image buffer = (System.Drawing.Image)bufferIn;
                               buffer.Save(ns, System.Drawing.Imaging.ImageFormat.Jpeg);// error comes here
                               ns.Close();
                               tcp.Close();
                            }
           }

Please give suggestions.

Answer 1

GDI+ images are not thread safe, you need to aquire lock on the object.

void SendVideoBuffer(object bufferIn) 
    { 

 var tcp = new TcpClient(ConfigurationSettings.AppSettings[0].ToString(), 6000); 
                   var ns = tcp.GetStream(); 
                   if (ns != null) 
                   { 
                       var buffer = (System.Drawing.Image)bufferIn;
                       lock(buffer) 
                            buffer.Save(ns, System.Drawing.Imaging.ImageFormat.Jpeg);
                       ns.Close(); 
                       tcp.Close(); 
        }
}