装了摄像头后一般会有 avicap32.dll文件,没有一样可以用这些代码。
不需要在解决方案里面引用这个.dll文件。
下面有二种写法的例子:
例一:

using System;

using System.Runtime.InteropServices;

using System.Drawing;

using System.Drawing.Imaging;


namespace WinVideo

{

/// <summary>

/// webcam 的摘要说明。

/// </summary>

public class webcam

{

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 bStat = false;


private IntPtr mControlPtr;

private int mWidth;

private int mHeight;

private int mLeft;

private int mTop;

private string GrabImagePath="";

private string KinescopePath="";


/// <summary>

/// 初始化摄像头

/// </summary>

/// <param name="handle">控件的句柄</param>

/// <param name="left">开始显示的左边距</param>

/// <param name="top">开始显示的上边距</param>

/// <param name="width">要显示的宽度</param>

/// <param name="height">要显示的长度</param>

public webcam(IntPtr handle,int left,int top,int width,int height)

{

mControlPtr=handle;

mWidth=width;

mHeight=height;

mLeft=left;

mTop=top;

}

"属性设置"


[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>

/// 开始显示图像

/// </summary>

public void Start()

{

if(bStat)

return;


bStat=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);

}

return;

}


/// <summary>

/// 停止显示

/// </summary>

public void Stop()

{

SendMessage(hWndC,WM_CAP_DRIVER_DISCONNECT,0,0);

bStat=false;

}


/// <summary>

/// 抓图

/// </summary>

/// <param name="path">要保存bmp文件的路径</param>

public void GrabImage()

{

IntPtr hBmp=Marshal.StringToHGlobalAnsi(GrabImagePath);

SendMessage(hWndC,WM_CAP_SAVEDIB,0,hBmp.ToInt64());


}


/// <summary>

/// 录像

/// </summary>

/// <param name="path">要保存avi文件的路径</param>

public void Kinescope()

{

IntPtr hBmp=Marshal.StringToHGlobalAnsi(KinescopePath);

SendMessage(hWndC,WM_CAP_FILE_SET_CAPTURE_FILEA,0,hBmp.ToInt64());

SendMessage(hWndC,WM_CAP_SEQUENCE,0,0);

}


/// <summary>

/// 停止录像

/// </summary>

public void StopKinescope()

{

SendMessage(hWndC,WM_CAP_STOP,0,0);

}

}

}
对该类的调用:

public webcam wcam=null;

private void Form1_Load(object sender, System.EventArgs e)

{

start();

this.btnKinescopeStop.Enabled=false;

}


private void btnStar_Click(object sender, System.EventArgs e)

{

wcam.Start();

}


private void btnStop_Click(object sender, System.EventArgs e)

{

wcam.Stop();

}


private void btnSnapPic_Click(object sender, System.EventArgs e)

{

//得到路径。例:d:/a.bmp

string myPath=this.txtPath.Text;

if(myPath=="")

{

MessageBox.Show("必须填写路径!");

return;

}

else

{

wcam.grabImagePath=myPath;

wcam.GrabImage();

MessageBox.Show("截图成功!");

}

}

public void start()

{

//以panel1为容器显示视频内容

wcam=new webcam(panel1.Handle,0,0,this.panel1.Width,this.panel1.Height);

wcam.Start();

}


private void panel1_SizeChanged(object sender, System.EventArgs e)

{

wcam.Stop();

wcam.Height=this.panel1.Height;

wcam.Width=this.panel1.Width;

wcam.Start();

}

private delegate void delegateKinescope();

private void btnKinescopeBegin_Click(object sender, System.EventArgs e)

{

//得到路径。例:d:/a.avi

string myPath=this.txtPath.Text;

if(myPath=="")

{

MessageBox.Show("必须填写路径!");

return;

}

else

{

wcam.kinescopePath=myPath;

delegateKinescope myK=new delegateKinescope(wcam.Kinescope);

Thread threadKinescope=new Thread(new ThreadStart(myK));

threadKinescope.Start();

this.btnKinescopeBegin.Enabled=false;

this.btnKinescopeStop.Enabled=true;

}

}

public void starKinescope()

{

delegateKinescope myK=new delegateKinescope(wcam.Kinescope);

}


private void btnKinescopeStop_Click(object sender, System.EventArgs e)

{

wcam.StopKinescope();

this.btnKinescopeBegin.Enabled=true;

this.btnKinescopeStop.Enabled=false;

}
例二:

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);

}

}


}
调用代码:

WebCamera wc;


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();

}