调用avicap32.dll第一次成功，以后都无法调用

requiem01119 2013-08-21 09:15:57

调用avicap32.dll第一次成功，以后都无法调用，picturebox里面剩下的都是黑色的，摄像头灯也没有亮，调用不成功。还有一个问题是我的摄像头不能定位到中心位置。求大神帮忙。

下面是源码

这个是form1的文件



using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.Runtime.InteropServices;

using System.Threading;





namespace AutoCam

{

    public partial class form1 : Form

    {



        public form1()

        {

            InitializeComponent();

        }

        Camera camera;



        #region InitializeComponent

        

        #region 

            btn_openCamera...

        #endregion



        private void button1_Click(object sender, EventArgs e)

        {

            this.btn_openCamera.Enabled = false;

            this.btn_closeCam.Enabled = true;

            this.btn_cameraPic.Enabled = true;

            camera = new Camera(this.pic_camera.Handle, this.pic_camera.Width, this.pic_camera.Height);

            camera.StartWebCam();

        }

        #endregion



        #region btn_closeCam_Click

        private void btn_closeCam_Click(object sender, EventArgs e)

        {

            this.btn_openCamera.Enabled = true;

            this.btn_closeCam.Enabled = false;

            this.btn_cameraPic.Enabled = false;

            camera.CloseWebcam();

        }

        #endregion



        #region btn_cameraPic_Click

        private void btn_cameraPic_Click(object sender, EventArgs e)

        {

            camera.GrabImage(this.pic_camera.Handle, "guying.bmp");

        }

        #endregion



        private void quit_Click(object sender, EventArgs e)

        {

            this.Close();

        }

    }

}

这个是cameraAPI.cs的文件



using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.Runtime.InteropServices;

using System.Threading;



namespace AutoCam

{

    class CameraAPI

    {

        [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);



        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_PREVIEWFORMAT = WM_USER + 45;

        public const int WM_CAP_SET_PREVIEWRATE = WM_USER + 52;

        public const int WM_CAP_START = WM_USER;

        public const int WM_CAP_SAVEDIB = WM_CAP_START + 25;

    }

}

这个是camera.cs的class用来生成cameraAPI实例



using System;

using System.Collections.Generic;

using System.Text;

using System.Threading;

using System.Runtime.InteropServices;

using System.IO;

using System.Windows;



namespace AutoCam

{



    class Camera

    {

        private IntPtr lwndC;

        private IntPtr mControlPtr;

        private int mWidth;

        private int mHeight;



        public Camera(IntPtr handel, int width, int height)

        {

            mControlPtr = handel; //handle of video dom

            mWidth = width; //video width

            mHeight = height; //video height

        }



        public void StartWebCam()

        {

            byte[] lpszName = new byte[100];

            byte[] lpszVer = new byte[100];

            CameraAPI.capGetDriverDescriptionA(0, lpszName,100, lpszVer, 0);

            this.lwndC = CameraAPI.capCreateCaptureWindowA(lpszName, CameraAPI.WS_CHILD | CameraAPI.WS_VISIBLE, 0, 0, mWidth, mHeight, mControlPtr, 0);

            if (CameraAPI.SendMessage(lwndC, CameraAPI.WM_CAP_DRIVER_CONNECT, 0, 0))

            {

                CameraAPI.SendMessage(lwndC, CameraAPI.WM_CAP_SET_PREVIEWRATE, 100, 0);

                CameraAPI.SendMessage(lwndC, CameraAPI.WM_CAP_SET_PREVIEW, true, 0);

            }

        }



        public void CloseWebcam()

        {

            CameraAPI.SendMessage(lwndC, CameraAPI.WM_CAP_DRIVER_DISCONNECT, 0, 0);

        }



        public void GrabImage(IntPtr hWndC, string path)

        {

            IntPtr hBmp = Marshal.StringToHGlobalAnsi(path);

            CameraAPI.SendMessage(lwndC, CameraAPI.WM_CAP_SAVEDIB, 0, hBmp.ToInt32());

        }

    }

}