c# 读取摄像头录像截图

using System;
　　using System.Runtime.InteropServices;
　　using System.Drawing;
　　using System.Drawing.Imaging;
　　namespace using System;
　　using System.Runtime.InteropServices;
　　using System.Drawing;
　　using System.Drawing.Imaging;
　　namespace PickHead
　　{
　　/// <summary>
　　/// 一个控制摄像头的类
　　/// </summary>
　　public class Pick
　　{
　　private const int WM_USER = 0x400;
　　private const int WS_CHILD = 0x40000000;
　　private const int WS_VISIBLE = 0x10000000;
　　private const int WM_CAP_START = WM_USER;
　　private const int WM_CAP_STOP = WM_CAP_START + 68;
　　private const int WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10;
　　private const int WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11;
　　private const int WM_CAP_SAVEDIB = WM_CAP_START + 25;
　　private const int WM_CAP_GRAB_FRAME = WM_CAP_START + 60;
　　private const int WM_CAP_SEQUENCE = WM_CAP_START + 62;
　　private const int WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START + 20;
　　private const int WM_CAP_SEQUENCE_NOFILE =WM_CAP_START+ 63;
　　private const int WM_CAP_SET_OVERLAY =WM_CAP_START+ 51; 
　　private const int WM_CAP_SET_PREVIEW =WM_CAP_START+ 50; 
　　private const int WM_CAP_SET_CALLBACK_VIDEOSTREAM = WM_CAP_START +6;
　　private const int WM_CAP_SET_CALLBACK_ERROR=WM_CAP_START +2;
　　private const int WM_CAP_SET_CALLBACK_STATUSA= WM_CAP_START +3;
　　private const int WM_CAP_SET_CALLBACK_FRAME= WM_CAP_START +5;
　　private const int WM_CAP_SET_SCALE=WM_CAP_START+ 53;
　　private const int WM_CAP_SET_PREVIEWRATE=WM_CAP_START+ 52; 
　　private IntPtr hWndC;
　　private bool bStat = false;
　　
　　private IntPtr mControlPtr;
　　private int mWidth;
　　private int mHeight;
　　private int mLeft;
　　private int mTop;
　　
　　/// <summary>
　　/// 初始化摄像头
　　/// </summary>
　　/// <param name="handle">控件的句柄</param>
　　/// <param name="left">开始显示的左边距</param>
　　/// <param name="top">开始显示的上边距</param>
　　/// <param name="width">要显示的宽度</param>
　　/// <param name="height">要显示的长度</param>
　　public Pick(IntPtr handle, int left, int top, int width,int height)
　　{
　　mControlPtr = handle;
　　mWidth = width;
　　mHeight = height;

[page_break]mLeft = left;
　　mTop = top;
　　}
　　[DllImport("avicap32.dll")] 
　　private static extern IntPtr capCreateCaptureWindowA(byte[] lpszWindowName, int dwStyle, int x, int y, int nWidth, int nHeight, IntPtr hWndParent, int nID);
　　
　　[DllImport("avicap32.dll")]
　　private static extern int capGetVideoFormat(IntPtr hWnd, IntPtr psVideoFormat, int wSize );
　　[DllImport("User32.dll")] 
　　private static extern bool SendMessage(IntPtr hWnd, int wMsg, int wParam, long lParam);
　　/// <summary>
　　/// 开始显示图像
　　/// </summary>
　　public void Start()
　　{
　　if (bStat)
　　return;
　　
　　bStat = true;
　　byte[] lpszName = new byte[100];
　　
　　hWndC = capCreateCaptureWindowA(lpszName,WS_CHILD|WS_VISIBLE ,mLeft,mTop,mWidth,mHeight,mControlPtr,0);
　　if (hWndC.ToInt32() != 0)
　　{
　　SendMessage(hWndC, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, 0);
　　SendMessage(hWndC, WM_CAP_SET_CALLBACK_ERROR, 0, 0);
　　SendMessage(hWndC, WM_CAP_SET_CALLBACK_STATUSA, 0, 0);
　　SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0);
　　SendMessage(hWndC, WM_CAP_SET_SCALE, 1, 0);
　　SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, 66, 0);
　　SendMessage(hWndC, WM_CAP_SET_OVERLAY, 1, 0);
　　SendMessage(hWndC, WM_CAP_SET_PREVIEW, 1, 0);
　　}
　　return;
　　}
　　/// <summary>
　　/// 停止显示

[page_break]/// </summary>
　　public void Stop()
　　{
　　SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
　　bStat = false;
　　}
　　/// <summary>
　　/// 抓图
　　/// </summary>
　　/// <param name="path">要保存bmp文件的路径</param>
　　public void GrabImage(string path)
　　{
　　
　　IntPtr hBmp = Marshal.StringToHGlobalAnsi(path);
　　SendMessage(hWndC,WM_CAP_SAVEDIB,0,hBmp.ToInt64());
　　}
　　/// <summary>
　　/// 录像
　　/// </summary>
　　/// <param name="path">要保存avi文件的路径</param>
　　public void Kinescope(string path)
　　{
　　IntPtr hBmp = Marshal.StringToHGlobalAnsi(path);
　　SendMessage(hWndC,WM_CAP_FILE_SET_CAPTURE_FILEA,0,hBmp.ToInt64());
　　SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0);
　　}
　　/// <summary>
　　/// 停止录像
　　/// </summary>
　　public void StopKinescope()
　　{
　　SendMessage(hWndC, WM_CAP_STOP, 0, 0);
　　}
　　}
　　}