[源码] C#打开摄像头抓取照片然后退出

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, 379, 316);
            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 + 10;
        public const int WM_CAP_DRIVER_DISCONNECT = WM_USER + 11;
        public const int WM_CAP_SET_CALLBACK_FRAME = WM_USER + 5;
        public const int WM_CAP_SET_PREVIEW = WM_USER + 50;
        public const int WM_CAP_SET_PREVIEWRATE = WM_USER + 52;
        public const int WM_CAP_SET_VIDEOFORMAT = WM_USER + 45;
        public const int WM_CAP_START = WM_USER;
        public const int WM_CAP_SAVEDIB = WM_CAP_START + 25;
    }
    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[100];
            byte[] lpszVer = new byte[100];
            VideoAPI.capGetDriverDescriptionA(0, lpszName, 100, lpszVer, 100);
            this.lwndC = VideoAPI.capCreateCaptureWindowA(lpszName, VideoAPI.WS_CHILD | VideoAPI.WS_VISIBLE, 0, 0, mWidth, mHeight, mControlPtr, 0);
            if (VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_DRIVER_CONNECT, 0, 0))
            {
                VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SET_PREVIEWRATE, 100, 0);
                VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SET_PREVIEW, true, 0);
            }
        }
        /// <summary>
        /// 关闭视频设备
        /// </summary>
        public void CloseWebcam()
        {
            VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_DRIVER_DISCONNECT, 0, 0);
        }
        ///   <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, 0, 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();
            }
            }
        }
    }

}

VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SAVEDIB, 0, hBmp.ToInt32());