使用海康摄像头采集图像时，需要在图像上添加图标、文字等额外数据。可选择使用SDK提供的NET_DVR_RigisterDrawFun()函数注册绘图回调函数，使用NET_DVR_RealPlay_V40()的返回值（用于在DrawFun()函数中区分通道数据）及DrawFun回调函数的指针进行注册。注意：使用DrawFun回调函数，需要在调用NET_DVR_RealPlay_V40()时将第三个参数设置为null。

class DeviceCamera : IDeviceCamera { private CameraInfo m_stCameraInfo; private bool m_bInitSDK = false; private Int32 m_lUserID = -1; private Int32 m_lRealHandle = -1; private CHCNetSDK.DRAWFUN cbDrawFun = null; public override bool InitCamera( CameraInfo stInfo ) { m_stCameraInfo = stInfo; // m_bInitSDK = CHCNetSDK.NET_DVR_Init(); if ( m_bInitSDK == false ) { uint nError = CHCNetSDK.NET_DVR_GetLastError(); MessageBox.Show( "NET_DVR_Init error! ErrorCode: " + nError ); return false; } else CHCNetSDK.NET_DVR_SetLogToFile( 3, "C:\\SdkLog\\", true ); CHCNetSDK.NET_DVR_SetConnectTime( 5000, 1 ); CHCNetSDK.NET_DVR_SetReconnect( 10000, 1 ); string DVRIPAddress = stInfo.strIP; Int16 DVRPortNumber = stInfo.nPort; string DVRUserName = stInfo.strUserName; string DVRPassword = stInfo.strPassword; CHCNetSDK.NET_DVR_DEVICEINFO_V30 DeviceInfo = new CHCNetSDK.NET_DVR_DEVICEINFO_V30(); m_lUserID = CHCNetSDK.NET_DVR_Login_V30( DVRIPAddress, DVRPortNumber, DVRUserName, DVRPassword, ref DeviceInfo ); if ( m_lUserID < 0 ) { MessageBox.Show( "登录失败！" ); CHCNetSDK.NET_DVR_Cleanup(); return false; } // CHCNetSDK.NET_DVR_PREVIEWINFO lpPreviewInfo = new CHCNetSDK.NET_DVR_PREVIEWINFO() { dwStreamType = 0, dwLinkMode = 0, bBlocked = true, dwDisplayBufNum = 10, }; //遍历PictureBox列表 cbDrawFun = new CHCNetSDK.DRAWFUN( fDrawFun ); int nPicBoxSize = m_stCameraInfo.lstPicBoxHdc.Count() <= 4 ? m_stCameraInfo.lstPicBoxHdc.Count() : 4; //海康摄像头模拟通道数 <= 4 for ( int nPicBoxIndex = 1; nPicBoxIndex <= nPicBoxSize; nPicBoxIndex++ ) { lpPreviewInfo.hPlayWnd = m_stCameraInfo.lstPicBoxHdc[ nPicBoxIndex - 1 ]; lpPreviewInfo.lChannel = nPicBoxIndex; m_lRealHandle = CHCNetSDK.NET_DVR_RealPlay_V40( m_lUserID, ref lpPreviewInfo, null, new IntPtr() ); //设置异常消息回调函数 bool bRet = CHCNetSDK.NET_DVR_SetExceptionCallBack_V30( 0, lpPreviewInfo.hPlayWnd, new CHCNetSDK.EXCEPYIONCALLBACK( cbException ), new IntPtr() ); if ( !bRet ) MessageBox.Show( "设置异常消息回调函数失败！" ); //注册绘图回调函数 bRet = CHCNetSDK.NET_DVR_RigisterDrawFun( m_lRealHandle, cbDrawFun, 0 ); if ( !bRet ) { MessageBox.Show( "注册绘图回调函数失败！" ); return false; } } return true; } private void fDrawFun( int lRealHandle, IntPtr hDC, uint dwUser ) { try { Graphics pDC = Graphics.FromHdc( hDC ); if ( null == pDC ) return; Brush hBrush = new SolidBrush( Color.Red ); Pen pen = new Pen( hBrush ); Rectangle rectTmp = new Rectangle( 100, 100, 100, 100 ); if( 0 == lRealHandle )//Channel 1 { //Image Bitmap img = new Bitmap( "../Images/NucSource.png" ); pDC.DrawImage( img, rectTmp ); //Text string strText = "Novel RPS"; Font font = new Font( "黑体", 18, FontStyle.Italic | FontStyle.Bold ); Point pt = new Point( 100, 75 ); pDC.DrawString( strText, font, hBrush, pt ); //Rectangle pDC.DrawRectangle( pen, rectTmp ); img.Dispose(); } else if ( 1 == lRealHandle )//Channel 2 { //Text string strText = "Novel RPS"; Font font = new Font( "黑体", 18, FontStyle.Italic | FontStyle.Bold ); Point pt = new Point( 100, 75 ); pDC.DrawString( strText, font, hBrush, pt ); } else if ( 2 == lRealHandle )//Channel 3 { //Rectangle pDC.DrawRectangle( pen, rectTmp ); } else if ( 3 == lRealHandle )//Channel 4 { //Image Bitmap img = new Bitmap( "../Images/NucSource.png" ); pDC.DrawImage( img, rectTmp ); img.Dispose(); } hBrush.Dispose(); pen.Dispose(); pDC.Dispose(); } catch { uint nError = CHCNetSDK.NET_DVR_GetLastError(); if( nError != 0 ) MessageBox.Show( "cbDrawFun -- Catch Error Code: " + nError ); } } private void cbException( uint dwType, int lUserID, int lHandle, IntPtr pUser ) { switch( dwType ) { case 0x8000: MessageBox.Show( "语音对讲时网络异常！" ); break; case 0x8002: MessageBox.Show( "报警上传时网络异常！" ); break; case 0x8003: MessageBox.Show( "网络预览时网络异常！" ); break; case 0x8004: MessageBox.Show( "透明通道传输时网络异常！" ); break; case 0x8005: MessageBox.Show( "预览时重连！" ); break; default: MessageBox.Show( "摄像头默认异常！" ); break; } } }

注：代码中使用PictureBox显示摄像头图像，故将其句柄设置给 lpPreviewInfo.hPlayWnd。