using System;

using System.Runtime.InteropServices;

public class VideoAPI //视频API类

{

    // 视频API调用

    [DllImport("avicap32.dll")]

    public static extern IntPtr capCreateCaptureWindowA(byte[] lpszWindowName, int dwStyle, int x, int y, int nWidth, int nHeight, IntPtr hWndParent, int nID);

    [DllImport("avicap32.dll")]

    public static extern bool capGetDriverDescriptionA(short wDriver, byte[] lpszName, int cbName, byte[] lpszVer, int cbVer);

    [DllImport("User32.dll")]

    public static extern bool SendMessage(IntPtr hWnd, int wMsg, bool wParam, int lParam);

    [DllImport("User32.dll")]

    public static extern bool SendMessage(IntPtr hWnd, int wMsg, short wParam, int lParam);

    // 常量

    public const int WM_USER = 0x400;

    public const int WS_CHILD = 0x40000000;

    public const int WS_VISIBLE = 0x10000000;

    public const int SWP_NOMOVE = 0x2;

    public const int SWP_NOZORDER = 0x4;

    public const int WM_CAP_DRIVER_CONNECT = WM_USER + ;

    public const int WM_CAP_DRIVER_DISCONNECT = WM_USER + ;

    public const int WM_CAP_SET_CALLBACK_FRAME = WM_USER + ;

    public const int WM_CAP_SET_PREVIEW = WM_USER + ;

    public const int WM_CAP_SET_PREVIEWRATE = WM_USER + ;

    public const int WM_CAP_SET_VIDEOFORMAT = WM_USER + ;

    public const int WM_CAP_START = WM_USER;

    public const int WM_CAP_SAVEDIB = WM_CAP_START + ;

}

public class cVideo //视频类

{

    private IntPtr lwndC; //保存无符号句柄

    private IntPtr mControlPtr; //保存管理指示器

    private int mWidth;

    private int mHeight;

    public cVideo(IntPtr handle, int width, int height)

    {

        mControlPtr = handle; //显示视频控件的句柄

        mWidth = width; //视频宽度

        mHeight = height; //视频高度

    }

    /// <summary>

    /// 打开视频设备

    /// </summary>

    public void StartWebCam()

    {

        byte[] lpszName = new byte[];

        byte[] lpszVer = new byte[];

        VideoAPI.capGetDriverDescriptionA(, lpszName, , lpszVer, );

        this.lwndC = VideoAPI.capCreateCaptureWindowA(lpszName, VideoAPI.WS_CHILD | VideoAPI.WS_VISIBLE, , , mWidth, mHeight, mControlPtr, );

        if (VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_DRIVER_CONNECT, , ))

        {

            VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SET_PREVIEWRATE, , );

            VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SET_PREVIEW, true, );

        }

    }

    /// <summary>

    /// 关闭视频设备

    /// </summary>

    public void CloseWebcam()

    {

        VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_DRIVER_DISCONNECT, , );

    }

    /// <summary>

    /// 拍照

    /// </summary>

    /// <param name="path">要保存bmp文件的路径</param>

    public void GrabImage(IntPtr hWndC, string path)

    {

        IntPtr hBmp = Marshal.StringToHGlobalAnsi(path);

        VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SAVEDIB, , hBmp.ToInt32());

    }

}