源码如下，求高手指点


using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Drawing.Imaging;
using
using
using System.Threading;
namespace camera
{

    //Socket tmpClient = null;
    public partial class CameraForm : Form
    {
        private int hHwnd;
        private const int port = 2000;
        public CameraForm()
        {
            InitializeComponent();
        }
        public struct videohdr_tag
        {
            public byte[] lpData;
            public int dwBufferLength;
            public int dwBytesUsed;
            public int dwTimeCaptured;
            public int dwUser;
            public int dwFlags;
            public int[] dwReserved;

        }
        public delegate bool CallBack(int hwnd, int lParam);
        ///   <summary>   
        ///   必需的设计器变量。   
        ///   </summary>   
        //private components = null;
        [DllImport("avicap32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
        public static extern int capCreateCaptureWindowA([MarshalAs(UnmanagedType.VBByRefStr)]   ref   string lpszWindowName, int dwStyle, int x, int y, int nWidth, short nHeight, int hWndParent, int nID);
        [DllImport("avicap32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
        public static extern bool capGetDriverDescriptionA(short wDriver, [MarshalAs(UnmanagedType.VBByRefStr)]   ref   string lpszName, int cbName, [MarshalAs(UnmanagedType.VBByRefStr)]   ref   string lpszVer, int cbVer);
        [DllImport("user32", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
        public static extern bool DestroyWindow(int hndw);
        [DllImport("user32", EntryPoint = "SendMessageA", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
        public static extern int SendMessage(int hwnd, int wMsg, int wParam, [MarshalAs(UnmanagedType.AsAny)]   object lParam);
        [DllImport("user32", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
        public static extern int SetWindowPos(int hwnd, int hWndInsertAfter, int x, int y, int cx, int cy, int wFlags);
        [DllImport("vfw32.dll")]
        public static extern string capVideoStreamCallback(int hwnd, videohdr_tag videohdr_tag);
        [DllImport("vicap32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
        public static extern bool capSetCallbackOnFrame(int hwnd, string s);

        private void OpenCapture()
        {
            int intWidth = this.panel1.Width;
            int intHeight = this.panel1.Height;
            int intDevice = 0;
            string refDevice = intDevice.ToString();
            //创建视频窗口并得到句柄
            hHwnd = CameraForm.capCreateCaptureWindowA(ref   refDevice, 1342177280, 0, 0, 640, 480, this.panel1.Handle.ToInt32(), 0);
            if (CameraForm.SendMessage(hHwnd, 0x40a, intDevice, 0) > 0)
            {
                CameraForm.SendMessage(this.hHwnd, 0x435, -1, 0);
                CameraForm.SendMessage(this.hHwnd, 0x434, 0x42, 0);
                CameraForm.SendMessage(this.hHwnd, 0x432, -1, 0);
                CameraForm.SetWindowPos(this.hHwnd, 1, 0, 0, intWidth, intHeight, 6);
            }
            else
            {
                CameraForm.DestroyWindow(this.hHwnd);
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.OpenCapture();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            //停止视频注销视频句柄
            CameraForm.SendMessage(this.hHwnd, 0x40b, 0, 0);
            CameraForm.DestroyWindow(this.hHwnd);
        }

        //截图
        private void button3_Click(object sender, EventArgs e)
        {
            try
            {
                CameraForm.SendMessage(this.hHwnd, 0x41e, 0, 0);
                IDataObject obj1 = Clipboard.GetDataObject();
                if (obj1.GetDataPresent(typeof(Bitmap)))
                {
                    Image image1 = (Image)obj1.GetData(typeof(Bitmap));
                    SaveFileDialog SaveFileDialog1 = new SaveFileDialog();
                    SaveFileDialog1.FileName = DateTime.Now.ToString("yyyyMMddhhmmss");
                    SaveFileDialog1.Filter = "Image Files(*.JPG;*.GIF)|*.JPG;*.GIF|All files (*.*)|*.*";
                    if (SaveFileDialog1.ShowDialog() == DialogResult.OK)
                    {
                        image1.Save(SaveFileDialog1.FileName, ImageFormat.Bmp);
                    }
                }
            }
            catch
            {
            }
        }

    }
}