C#摄像头编程

这段时间搞视频采集方面的程序，在国外网站上找到一个用C#写的驱动摄像头的程序。
经改造和调试，如下：
(1)安装摄像头后，一般可以找到一个avicap32.dll文件(2)这是一个关于摄像头的类:
using System;
 using System.Runtime.InteropServices;namespace webcam
 {
  /// 
  /// avicap 的摘要说明。
  /// 
  public class showVideo
  {
   // showVideo calls
   [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); 
   [DllImport("User32.dll")] 
   public static extern bool SendMessage(IntPtr hWnd, int wMsg, short wParam, FrameEventHandler lParam); 
   [DllImport("User32.dll")] 
   public static extern bool SendMessage(IntPtr hWnd, int wMsg, int wParam, ref BITMAPINFO lParam);
   [DllImport("User32.dll")] 
   public static extern int SetWindowPos(IntPtr hWnd, int hWndInsertAfter, int x, int y, int cx, int cy, int wFlags);
   [DllImport("avicap32.dll")]
   public static extern int capGetVideoFormat(IntPtr hWnd, IntPtr psVideoFormat, int wSize );
  
   // Constants
   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;
      
   // Structures
   [StructLayout(LayoutKind.Sequential)] public struct VIDEOHDR
   {
    [MarshalAs(UnmanagedType.I4)] public int lpData;
    [MarshalAs(UnmanagedType.I4)] public int dwBufferLength;
    [MarshalAs(UnmanagedType.I4)] public int dwBytesUsed;
    [MarshalAs(UnmanagedType.I4)] public int dwTimeCaptured;
    [MarshalAs(UnmanagedType.I4)] public int dwUser;
    [MarshalAs(UnmanagedType.I4)] public int dwFlags;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst=4)] public int[] dwReserved;
   }
  
   [StructLayout(LayoutKind.Sequential)] public struct BITMAPINFOHEADER
   {
    [MarshalAs(UnmanagedType.I4)] public Int32 biSize ;
    [MarshalAs(UnmanagedType.I4)] public Int32 biWidth ;
    [MarshalAs(UnmanagedType.I4)] public Int32 biHeight ;
    [MarshalAs(UnmanagedType.I2)] public short biPlanes;
    [MarshalAs(UnmanagedType.I2)] public short biBitCount ;
    [MarshalAs(UnmanagedType.I4)] public Int32 biCompression;
    [MarshalAs(UnmanagedType.I4)] public Int32 biSizeImage;
    [MarshalAs(UnmanagedType.I4)] public Int32 biXPelsPerMeter;
    [MarshalAs(UnmanagedType.I4)] public Int32 biYPelsPerMeter;
    [MarshalAs(UnmanagedType.I4)] public Int32 biClrUsed;
    [MarshalAs(UnmanagedType.I4)] public Int32 biClrImportant;
   } 
  
   [StructLayout(LayoutKind.Sequential)] public struct BITMAPINFO
   {
    [MarshalAs(UnmanagedType.Struct, SizeConst=40)] public BITMAPINFOHEADER bmiHeader;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst=1024)] public Int32[] bmiColors;
   }
      
   public delegate void FrameEventHandler(IntPtr lwnd, IntPtr lpVHdr);
      
   // Public methods
   public static object GetStructure(IntPtr ptr,ValueType structure)
   {
    return Marshal.PtrToStructure(ptr,structure.GetType());
   }
   
   public static object GetStructure(int ptr,ValueType structure)
   {
    return GetStructure(new IntPtr(ptr),structure);
   }
      
   public static void Copy(IntPtr ptr,byte[] data)
   {
    Marshal.Copy(ptr,data,0,data.Length);
   }
      
   public static void Copy(int ptr,byte[] data)
   {
    Copy(new IntPtr(ptr),data);
   }
      
   public static int SizeOf(object structure)
   {
    return Marshal.SizeOf(structure); 
   }
  }  //Web Camera Class
  public class WebCamera
  {
   // Constructur
   public WebCamera(IntPtr handle, int width,int height)
   {
    mControlPtr = handle;
    mWidth = width;
    mHeight = height;
   }
      
   // delegate for frame callback
   public delegate void RecievedFrameEventHandler(byte[] data);
   public event RecievedFrameEventHandler RecievedFrame;
      
   private IntPtr lwndC; // Holds the unmanaged handle of the control
   private IntPtr mControlPtr; // Holds the managed pointer of the control
   private int mWidth;
   private int mHeight;
      
   private showVideo.FrameEventHandler mFrameEventHandler; // Delegate instance for the frame callback - must keep alive! gc should NOT collect it
      
   // Close the web camera
   public void CloseWebcam()
   {
    this.capDriverDisconnect(this.lwndC);
   }
      
   // start the web camera
   public void StartWebCam()
   {
    byte[] lpszName = new byte[100];
    byte[] lpszVer = new byte[100];
           
    showVideo.capGetDriverDescriptionA(0, lpszName, 100,lpszVer, 100);
    this.lwndC = showVideo.capCreateCaptureWindowA(lpszName, showVideo.WS_VISIBLE + showVideo.WS_CHILD, 0, 0, mWidth, mHeight, mControlPtr, 0);
           
    if (this.capDriverConnect(this.lwndC, 0))
    {
     this.capPreviewRate(this.lwndC, 66);
     this.capPreview(this.lwndC, true);
     showVideo.BITMAPINFO bitmapinfo = new showVideo.BITMAPINFO(); 
     bitmapinfo.bmiHeader.biSize = showVideo.SizeOf(bitmapinfo.bmiHeader);
     bitmapinfo.bmiHeader.biWidth = 352;
     bitmapinfo.bmiHeader.biHeight = 288;
     bitmapinfo.bmiHeader.biPlanes = 1;
     bitmapinfo.bmiHeader.biBitCount = 24;
     this.capSetVideoFormat(this.lwndC, ref bitmapinfo, showVideo.SizeOf(bitmapinfo));
     this.mFrameEventHandler = new showVideo.FrameEventHandler(FrameCallBack);
     this.capSetCallbackOnFrame(this.lwndC, this.mFrameEventHandler);
     showVideo.SetWindowPos(this.lwndC, 0, 0, 0, mWidth , mHeight , 6);
    } 
   }
  
   // private functions
   private bool capDriverConnect(IntPtr lwnd, short i)
   {
    return showVideo.SendMessage(lwnd, showVideo.WM_CAP_DRIVER_CONNECT, i, 0);
   }
  
   private bool capDriverDisconnect(IntPtr lwnd)
   {
    return showVideo.SendMessage(lwnd, showVideo.WM_CAP_DRIVER_DISCONNECT, 0, 0);
   }
      
   private bool capPreview(IntPtr lwnd, bool f)
   {
    return showVideo.SendMessage(lwnd, showVideo.WM_CAP_SET_PREVIEW , f, 0);
   }
  
   private bool capPreviewRate(IntPtr lwnd, short wMS)
   {
    return showVideo.SendMessage(lwnd, showVideo.WM_CAP_SET_PREVIEWRATE, wMS, 0);
   }
      
   private bool capSetCallbackOnFrame(IntPtr lwnd, showVideo.FrameEventHandler lpProc)
   {     
    return showVideo.SendMessage(lwnd, showVideo.WM_CAP_SET_CALLBACK_FRAME, 0, lpProc);
   }
  
   private bool capSetVideoFormat(IntPtr hCapWnd, ref showVideo.BITMAPINFO BmpFormat, int CapFormatSize)
   {
    return showVideo.SendMessage(hCapWnd, showVideo.WM_CAP_SET_VIDEOFORMAT, CapFormatSize, ref BmpFormat);
   }
  
   private void FrameCallBack(IntPtr lwnd, IntPtr lpVHdr)
   {
    showVideo.VIDEOHDR videoHeader = new showVideo.VIDEOHDR();
    byte[] VideoData;
    videoHeader = (showVideo.VIDEOHDR)showVideo.GetStructure(lpVHdr,videoHeader);
    VideoData = new byte[videoHeader.dwBytesUsed];
    showVideo.Copy(videoHeader.lpData ,VideoData);
    if (this.RecievedFrame != null)
     this.RecievedFrame (VideoData);
   }
  }
 }具体调用如下：
using System;
 using System.Drawing;
 using System.Collections;
 using System.ComponentModel;
 using System.Windows.Forms;
 using System.Data;
 using webcam;namespace webcam
 {
  /// 
  /// Form1 的摘要说明。
  /// 
  public class Form1 : System.Windows.Forms.Form
  {
   private System.Windows.Forms.Panel panelPreview;
   private System.Windows.Forms.Button b_play;
   private System.Windows.Forms.Button b_stop;
   /// 
   /// 必需的设计器变量。
   /// 
   private System.ComponentModel.Container components = null;
   WebCamera wc;  public Form1()
   {
    //
    // Windows 窗体设计器支持所必需的
    //
    InitializeComponent();   //
    // TODO: 在 InitializeComponent 调用后添加任何构造函数代码
    //
   }  /// 
   /// 清理所有正在使用的资源。
   /// 
   protected override void Dispose( bool disposing )
   {
    if( disposing )
    {
     if (components != null) 
     {
      components.Dispose();
     }
    }
    base.Dispose( disposing );
   }  #region Windows 窗体设计器生成的代码
   /// 
   /// 设计器支持所需的方法 - 不要使用代码编辑器修改
   /// 此方法的内容。
   /// 
   private void InitializeComponent()
   {
    this.b_play = new System.Windows.Forms.Button();
    this.panelPreview = new System.Windows.Forms.Panel();
    this.b_stop = new System.Windows.Forms.Button();
    this.SuspendLayout();
    // 
    // b_play
    // 
    this.b_play.Location = new System.Drawing.Point(280, 368);
    this.b_play.Name = "b_play";
    this.b_play.TabIndex = 0;
    this.b_play.Text = "&Play";
    this.b_play.Click += new System.EventHandler(this.button1_Click);
    // 
    // panelPreview
    // 
    this.panelPreview.Location = new System.Drawing.Point(8, 8);
    this.panelPreview.Name = "panelPreview";
    this.panelPreview.Size = new System.Drawing.Size(344, 272);
    this.panelPreview.TabIndex = 1;
    // 
    // b_stop
    // 
    this.b_stop.Enabled = false;
    this.b_stop.Location = new System.Drawing.Point(360, 368);
    this.b_stop.Name = "b_stop";
    this.b_stop.TabIndex = 2;
    this.b_stop.Text = "&Stop";
    this.b_stop.Click += new System.EventHandler(this.b_stop_Click);
    // 
    // Form1
    // 
    this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
    this.ClientSize = new System.Drawing.Size(464, 413);
    this.Controls.Add(this.b_stop);
    this.Controls.Add(this.panelPreview);
    this.Controls.Add(this.b_play);
    this.MaximizeBox = false;
    this.MinimizeBox = false;
    this.Name = "Form1";
    this.Text = "GoodView test Web Camera";
    this.Load += new System.EventHandler(this.Form1_Load);
    this.ResumeLayout(false);  }
   #endregion  /// 
   /// 应用程序的主入口点。
   /// 
   [STAThread]
   static void Main() 
   {
    Application.Run(new Form1());
   }  private void Form1_Load(object sender, System.EventArgs e)
   {
    b_play.Enabled = false;
    b_stop.Enabled = true;
    panelPreview.Size = new Size(330,330);
    wc = new WebCamera( panelPreview.Handle,panelPreview.Width,panelPreview.Height);
    wc.StartWebCam();
   }  private void button1_Click(object sender, System.EventArgs e)
   {
    b_play.Enabled = false;
    b_stop.Enabled = true;
    panelPreview.Size = new Size(330,330);
    wc = new WebCamera( panelPreview.Handle,panelPreview.Width,panelPreview.Height);
    wc.StartWebCam();
   }  private void b_stop_Click(object sender, System.EventArgs e)
   {
    b_play.Enabled = true;
    b_stop.Enabled = false;
    wc.CloseWebcam();
   }
  }
 }