.Net里一个用于驱动摄像头的类

　　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;