c# 摄像头 拍照

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices; 

namespace test
{
    class Class1
    {
    }

    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);

        [System.Runtime.InteropServices.DllImport("avicap32.dll")]
        static extern int capCreateCaptureWindowA(string lpszWindowName, int dwStyle, int x, int y, int nWidth, short nHeight, int 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);
        [DllImport("User32.dll")]
        public static extern int SetWindowPos(IntPtr hWnd, int hWndInsertAfter, int x, int y, int cx, int cy, int wFlags);
        //  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 = 2;
        public const int SWP_NOZORDER = 4;
        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_PREVIEWRATE = 1024 52;
        public const int WM_CAP_SET_SCALE = 1024 53;
        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, 640, 480, mControlPtr, 0);

            //int iHeight = 120;
            //int iWidth = 160;
            //// 
            ////  Open Preview window in picturebox
            //// 
            //hHwnd = capCreateCaptureWindowA(iDevice.ToString(), (WS_VISIBLE | WS_CHILD), 0, 0, 640, 480, picCapture.Handle.ToInt32(), 0);
            //// 
            ////  Connect to device
            //// 
            //if (SendMessage(hHwnd, WM_CAP_DRIVER_CONNECT, iDevice, 0) == 1)
            //{
            //    // 
            //    // Set the preview scale
            //    // 
            //    SendMessage(hHwnd, WM_CAP_SET_SCALE, 1, 0);
            //    // 
            //    // Set the preview rate in milliseconds
            //    // 
            //    SendMessage(hHwnd, WM_CAP_SET_PREVIEWRATE, 66, 0);
            //    // 
            //    // Start previewing the image from the camera
            //    // 
            //    SendMessage(hHwnd, WM_CAP_SET_PREVIEW, 1, 0);
            //    // 
            //    //  Resize window to fit in picturebox
            //    // 
            //    //SetWindowPos(hHwnd, HWND_BOTTOM, 0, 0, iWidth, iHeight, (SWP_NOMOVE | SWP_NOZORDER));
            //}

            if (VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_DRIVER_CONNECT, 0, 0))
            {
                VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SET_SCALE, 1, 0);
                VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SET_PREVIEWRATE, 66, 0);
                VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SET_PREVIEW, true, 0);

                VideoAPI.SetWindowPos(lwndC, 1, 0, 0, 160, 120, (VideoAPI.SWP_NOMOVE | VideoAPI.SWP_NOZORDER));

                //VideoAPI.SetWindowPos(this.lwndC, 0, 300, 300, 320, 460, 6);
            }
        }
        /// <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bmp文件的路径</param>   
        public void GrabImage(IntPtr hWndC, string path)
        {
            IntPtr hBmp = Marshal.StringToHGlobalAnsi(path);
            VideoAPI.SetWindowPos(lwndC, 1, 0, 0, 160, 120, (VideoAPI.SWP_NOMOVE | VideoAPI.SWP_NOZORDER));
            VideoAPI.SendMessage(lwndC, VideoAPI.WM_CAP_SAVEDIB, 0, hBmp.ToInt32());
        }
    }

}