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想用c#程序设计控制笔记本摄像头,代码编译通过,运行不报错,就是没有效果 RRS feed

  • 问题

  • 代码都是直接拷贝网上流传的c# 摄像头编程。

    摄像头类:

    public class Cams
        {
            [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);
            }
        }

    摄像头操作类:

    class CamsController
        {
            // 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 Cams.FrameEventHandler mFrameEventHandler;
     
            public CamsController(IntPtr handle, int width, int height)
            {
                mControlPtr = handle;
                mWidth = width;
                mHeight = height;
            }
     
            // private functions
            private bool capDriverConnect(IntPtr lwnd, short i)
            {
                return Cams.SendMessage(lwnd, Cams.WM_CAP_DRIVER_CONNECT, i, 0);
            }
            private bool capDriverDisconnect(IntPtr lwnd)
            {
                return Cams.SendMessage(lwnd, Cams.WM_CAP_DRIVER_DISCONNECT, 0, 0);
            }
            private bool capPreview(IntPtr lwnd, bool f)
            { return Cams.SendMessage(lwnd, Cams.WM_CAP_SET_PREVIEW, f, 0); }
     
            private bool capPreviewRate(IntPtr lwnd, short wMS)
            {
                return Cams.SendMessage(lwnd, Cams.WM_CAP_SET_PREVIEWRATE, wMS, 0);
            }
     
            private bool capSetCallbackOnFrame(IntPtr lwnd, Cams.FrameEventHandler lpProc)
            {
                return Cams.SendMessage(lwnd, Cams.WM_CAP_SET_CALLBACK_FRAME, 0, lpProc);
            }
     
            private bool capSetVideoFormat(IntPtr hCapWnd, ref Cams.BITMAPINFO BmpFormat, int CapFormatSize)
            {
                return Cams.SendMessage(hCapWnd, Cams.WM_CAP_SET_VIDEOFORMAT, CapFormatSize, ref BmpFormat);
            }
     
            private void FrameCallBack(IntPtr lwnd, IntPtr lpVHdr)
            {
                Cams.VIDEOHDR videoHeader = new Cams.VIDEOHDR();
                byte[] VideoData;
                videoHeader = (Cams.VIDEOHDR)Cams.GetStructure(lpVHdr, videoHeader);
                VideoData = new byte[videoHeader.dwBytesUsed];
                Cams.Copy(videoHeader.lpData, VideoData);
                if (this.RecievedFrame != null)
                    this.RecievedFrame(VideoData);
            }
     
            public void StartCam()
            {
                byte[] lpszName = new byte[100];
                byte[] lpszVer = new byte[100];
     
                Cams.capGetDriverDescriptionA(0, lpszName, 100, lpszVer, 100);
                this.lwndC = Cams.capCreateCaptureWindowA(lpszName, Cams.WS_VISIBLE + Cams.WS_CHILD, 0, 0, mWidth, mHeight, mControlPtr, 0);
     
                if (this.capDriverConnect(this.lwndC, 0))//这里往设备发送开启信号无反应
                {
                    this.capPreviewRate(this.lwndC, 66);
                    this.capPreview(this.lwndC, true);
                    Cams.BITMAPINFO bitmapinfo = new Cams.BITMAPINFO();
                    bitmapinfo.bmiHeader.biSize = Cams.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, Cams.SizeOf(bitmapinfo));
                    this.mFrameEventHandler = new Cams.FrameEventHandler(FrameCallBack);
                    this.capSetCallbackOnFrame(this.lwndC, this.mFrameEventHandler);
                    Cams.SetWindowPos(this.lwndC, 0, 0, 0, mWidth, mHeight, 6);
                }
            }
     

            public void CloseCams()
            {
                this.capDriverDisconnect(this.lwndC);
            }
        }

    加粗下划线的位置就是问题所在,代码跳到那个位置,往设备发生信息,但是返回结果为否,然后摄像头返回黑幕,求达人帮忙分析一下啊


    2012年5月3日 3:36

答案

  • 你好,

    这是所有的代码了吗?

    首先要确定的是代码中是否存在Try...catch的语句将某些exception给吃掉了。

    其次代码运行到那里没有反应并不代表程序在那边出了错误,请通过VS上的堆栈操作确定到底那边出错了

    2012年5月4日 10:09

全部回复

  • 你好,

    这是所有的代码了吗?

    首先要确定的是代码中是否存在Try...catch的语句将某些exception给吃掉了。

    其次代码运行到那里没有反应并不代表程序在那边出了错误,请通过VS上的堆栈操作确定到底那边出错了

    2012年5月4日 10:09
  • 你好,

    这是所有的代码了吗?

    首先要确定的是代码中是否存在Try...catch的语句将某些exception给吃掉了。

    其次代码运行到那里没有反应并不代表程序在那边出了错误,请通过VS上的堆栈操作确定到底那边出错了


    没出差,无论怎都catch不到错误的,仅仅是往设备发送开启信号不成功,但是大部分例子都是这样发送的,所以好费解

    2012年5月10日 2:54
  • 建议使用F5 调试一下,到这段 将出错信息发布来。方便解决你所遇到的问题

    爱吃西瓜的小强[mcpd]


    2012年5月10日 7:06
  • 就是调试没有错误,handle成功取得,就是摄像头没有反应

    2012年5月29日 7:02