C#调用摄像头

using System;using System.Collections.Generic;using System.Text;using System.Runtime.InteropServices;public class VideoWork{    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 bWorkStart = false;    private IntPtr mControlPtr;    private int mWidth;    private int mHeight;    private int mLeft;    private int mTop;    /**/    ///   <summary>     ///   初始化显示图像     ///   </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 VideoWork(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);    //     //这里特别注意，因为WinAPI中的long为32位，而C#中的long为64wei，所以需要将lParam该为int     //     [DllImport("User32.dll ")]    private static extern bool SendMessage(IntPtr hWnd, int wMsg, int wParam, int lParam);    /**/    ///   <summary>     ///   开始显示图像     ///   </summary>     public void Start()    {        if (bWorkStart)            return;        bWorkStart = 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);            //Global.log.Write( "SendMessage ");         }        return;    }    /**/    ///   <summary>     ///   停止显示     ///   </summary>     public void Stop()    {        SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);        bWorkStart = 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.ToInt32());    }}

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