using System;

using System.Collections.Generic;

using System.Text;

using System.Diagnostics;

namespace MyVideoService

{

    class Program

    {

        static void Main(string[] args)

        {

            cVideo video = new cVideo(Process.GetCurrentProcess().MainWindowHandle, , );

            video.StartWebCam();

            video.GrabImage(Process.GetCurrentProcess().MainWindowHandle, "d:\\b.jpg");

            video.CloseWebcam();

        }

    }

}

using System;

using System.Collections.Generic;

using System.Text;

using System.Runtime.InteropServices;

using System.Drawing.Imaging;

using System.Drawing;

using System.IO;

namespace MyVideoService

{

    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jpeg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());

            Bitmap image = new Bitmap(path);

            if (path.Contains("bmp"))

            {

                image.Save(path.Replace("bmp", "jpg"), ImageFormat.Jpeg);

                image.Dispose();

                if (System.IO.File.Exists(path))

                {

                    try

                    {

                        System.IO.File.Delete(path);

                    }

                    catch (System.IO.IOException e)

                    {

                        return;

                    }

            }

            else {

                image.Save(path, ImageFormat.Jpeg);

                image.Dispose();

            }

            }

        }

    }

}