c# 網路攝影機截圖

using System;using System.Runtime.InteropServices;using System.Drawing;using System.Drawing.Imaging;namespace Video{/// <summary>/// 一個控制網路攝影機的類/// </summary>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>/// 初始化顯示映像/// </summary>/// <param name="handle">控制項的控制代碼</param>/// <param name="left">開始顯示的左邊距</param>/// <param name="top">開始顯示的上邊距</param>/// <param name="width">要顯示的寬度</param>/// <param name="height">要顯示的長度</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 );[DllImport("User32.dll")] private static extern bool SendMessage(IntPtr hWnd, int wMsg, int wParam, long lParam);/// <summary>/// 開始顯示映像/// </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>/// 停止顯示/// </summary>public void Stop(){SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);bWorkStart = false;}/// <summary>/// 抓圖/// </summary>/// <param name="path">要儲存bmp檔案的路徑</param>public void GrabImage(string path){IntPtr hBmp = Marshal.StringToHGlobalAnsi(path);SendMessage(hWndC,WM_CAP_SAVEDIB,0,hBmp.ToInt64());}}}