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

Question

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

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傻

Answer 1

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

Answer 2

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

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傻

Answer 3

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

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爱吃西瓜的小强[mcpd]

Answer 4

就是调试没有错误，handle成功取得，就是摄像头没有反应

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傻