C#实现控制摄像头的类

/// <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;   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  /// </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);  }}