int ISampleGrabberCB.BufferCB(double SampleTime, IntPtr pBuffer, int BufferLen)

        {

            try

            {

                if (!mbGotOne)

                {

                    // The buffer should be long enought

                    if (BufferLen <= mstride * mvideoHeight)

                    {

                        // Copy the frame to the buffer

                //        m_handle = pBuffer;

                        CopyMemory(mhandle, pBuffer, mstride * mvideoHeight);

                        // m_handle = pBuffer;

                        mbGotOne = true;//这里弹出错误。

                        // Picture is ready.

                        mpictureReady.Set();

                    }                

                }

                else

                {

                    mdropped++;

                }

            }

            catch (System.Exception ex)

            {

                MessageBox.Show(ex.ToString());

           &n