多线程无法正常使用VedioCapture类

有人用过VedioCapture类吗？就是c#下的视频采集类，挺好用的，可是我现在发现多线程下似乎无法获取图片，
using System;
using System.Runtime.InteropServices;
using System.Threading;
namespace ReboundServer
{
    /// 
    /// VedioCapture 的摘要说明。
    /// 
    public class VedioCapture 
    {
        private int hCaptureM;
        private bool isUnLoad = false;        public VedioCapture ()
        {
        }        [DllImport("avicap32.dll")]
        private static extern int capCreateCaptureWindow(string strWindowName, int dwStyle, int x, int y, int width, int height, int hwdParent, int nID);
        [DllImport("user32.dll")]
        private static extern int SendMessage(int hwnd, int wMsg, int wParam, int lParam);
        [DllImport("user32.dll")]
        private static extern int SendMessage(int hwnd, int wMsg, int wParam, string lParam);
        [DllImport("Kernel32.dll")]
        private static extern bool CloseHandle(int hObject);        public bool Initialize(System.Windows.Forms.Control aContainer, int intWidth, int intHeight)
        {
            hCaptureM = capCreateCaptureWindow("", 0x40000000 | 0x10000000, 0, 0, intWidth, intHeight, aContainer.Handle.ToInt32(), 1);
            if (hCaptureM == 0) return false;            int ret = SendMessage(hCaptureM, 1034, 0, 0);
            if (ret == 0)
            {
                CloseHandle(hCaptureM);
                return false;
            }
            //WM_CAP_SET_PREVIEW
            ret = SendMessage(hCaptureM, 1074, 1, 0);
            if (ret == 0)
            {
                this.UnLoad();
                return false;
            }
            //WM_CAP_SET_SCALE
            ret = SendMessage(hCaptureM, 1077, 1, 0);
            if (ret == 0)
            {
                this.UnLoad();
                return false;
            }
            //WM_CAP_SET_PREVIEWRATE
            ret = SendMessage(hCaptureM, 1076, 66, 0);
            if (ret == 0)
            {
                this.UnLoad();
                return false;
            }
            return true;
        }        public void SingleFrameBegin()
        {
            //
            int ret = SendMessage(hCaptureM, 1094, 0, 0);
        }        public void SingleFrameEnd()
        {
            //
            int ret = SendMessage(hCaptureM, 1095, 0, 0);
        }        public void SingleFrameMode()
        {
            //WM_CAP_GRAB_FRAME
            int ret = SendMessage(hCaptureM, 1084, 0, 0);
            //WM_CAP_SET_PREVIEW 
            //int ret = SendMessage(  hCaptureM, 1074 , 0, 0 );
            //WM_CAP_SINGLE_FRAME
            //ret = SendMessage( hCaptureM, 1096 , 0, 0 );
        }        public void PreviewMode()
        {
            int ret = SendMessage(hCaptureM, 1074, 1, 0);
        }        public void UnLoad()
        {
            int ret = SendMessage(hCaptureM, 1035, 0, 0);
            CloseHandle(this.hCaptureM);
            isUnLoad = true;
        }        public void CopyToClipBorad()
        {
            int ret = SendMessage(hCaptureM, 1054, 0, 0);
        }        public System.Drawing.Image getCaptureImage()
        {
            System.Windows.Forms.IDataObject iData = System.Windows.Forms.Clipboard.GetDataObject();
            System.Drawing.Image retImage = null;
            if (iData != null)
            {
                if (iData.GetDataPresent(System.Windows.Forms.DataFormats.Bitmap))
                {
                    retImage = (System.Drawing.Image)iData.GetData(System.Windows.Forms.DataFormats.Bitmap);
                }
                else if (iData.GetDataPresent(System.Windows.Forms.DataFormats.Dib))
                {
                    retImage = (System.Drawing.Image)iData.GetData(System.Windows.Forms.DataFormats.Dib);
                }
            }
            return retImage;
        }
        ~AVG()
        {
            if (!isUnLoad)
            {
                this.UnLoad();
            }
        }
    }
}
在windows程序中直接调用一切正常，可是我想通过多线程进行截取pictureBox上的图片时没有办法截取到getCaptureImage函数中始终无法得到Clipboard上的数据，请问这是怎么回事，有办法解决吗？望请达人帮忙解答