需要按钮上的帮助来打开基于c#的QR码项目的网络摄像头

我目前正在学习QR码网络摄像头解码器。我从https://zxingnet.svn.codeplex.com/svn/trunk/Clients/AForgeDemo/采取了一个例子，并成功地建立它没有错误。然而，当我运行它与我的网络摄像头连接，没有输入或它不会打开网络摄像头。根据我的理解，当用户在组合框中选择它时，网络摄像头将被打开。好吧，因为在构建时没有错误，所以我无法确定哪里出错了。我还研究了一个项目，当用户按下按钮时，该项目会打开网络摄像头，我计划将其实现到当前项目中。我已经插入了按钮，但我不知道我应该在按钮上编程什么来打开网络摄像头，而不是选择在组合框

谁能给我建议或指导我通过它。下面是主程序，和2类

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;
    using AForge.Video;
    using ZXing;
    using System.Threading;

AForgeDemo

名称空间{公共的部分类AForgeDemoForm: Form{

    private struct Device
    {
        public int Index;
        public string Name;
        public override string ToString()
        {
            return Name;
        }
    }
    private readonly CameraDevices camDevices;
    private Bitmap currentBitmapForDecoding;
    private readonly Thread decodingThread;
    private Result currentResult;
    private readonly Pen resultRectPen;
    public AForgeDemoForm()
    {
        InitializeComponent();
        camDevices = new CameraDevices();
        decodingThread = new Thread(DecodeBarcode);
        decodingThread.Start();
        pictureBox1.Paint += pictureBox1_Paint;
        resultRectPen = new Pen(Color.Green, 10);
    }
    void pictureBox1_Paint(object sender, PaintEventArgs e)
  {
     if (currentResult == null)
        return;
     if (currentResult.ResultPoints != null && currentResult.ResultPoints.Length > 0)
     {
        var resultPoints = currentResult.ResultPoints;
        var rect = new Rectangle((int)resultPoints[0].X, (int)resultPoints[0].Y, 1, 1);
        foreach (var point in resultPoints)
        {
           if (point.X < rect.Left)
              rect = new Rectangle((int)point.X, rect.Y, rect.Width + rect.X -            (int)point.X, rect.Height);
           if (point.X > rect.Right)
              rect = new Rectangle(rect.X, rect.Y, rect.Width + (int)point.X - rect.X, rect.Height);
           if (point.Y < rect.Top)
              rect = new Rectangle(rect.X, (int)point.Y, rect.Width, rect.Height + rect.Y - (int)point.Y);
           if (point.Y > rect.Bottom)
              rect = new Rectangle(rect.X, rect.Y, rect.Width, rect.Height + (int)point.Y - rect.Y);
        }
        using (var g = pictureBox1.CreateGraphics())
        {
           g.DrawRectangle(resultRectPen, rect);
        }
}

}OnLoad(EventArgs e){base.OnLoad (e);LoadDevicesToCombobox ();}

    protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
    {
        base.OnClosing(e);
        if (!e.Cancel)
        {
            decodingThread.Abort();
            if (camDevices.Current != null)
            {
                camDevices.Current.NewFrame -= Current_NewFrame;
                if (camDevices.Current.IsRunning)
                {
                    camDevices.Current.SignalToStop();
                }
            }
        }
    }
    private void LoadDevicesToCombobox()
    {
        cmbDevice.Items.Clear();
        for (var index = 0; index < camDevices.Devices.Count; index++)
        {
            cmbDevice.Items.Add(new Device { Index = index, Name = camDevices.Devices[index].Name });
        }
    }
    private void cmbDevice_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (camDevices.Current != null)
        {
            camDevices.Current.NewFrame -= Current_NewFrame;
            if (camDevices.Current.IsRunning)
            {
                camDevices.Current.SignalToStop();
            }
        }
        camDevices.SelectCamera(((Device)(cmbDevice.SelectedItem)).Index);
        camDevices.Current.NewFrame += Current_NewFrame;
        camDevices.Current.Start();
    }
    private void Current_NewFrame(object sender, NewFrameEventArgs eventArgs)
    {
        if (IsDisposed)
        {
            return;
        }
        try
        {
            if (currentBitmapForDecoding == null)
            {
                currentBitmapForDecoding = (Bitmap)eventArgs.Frame.Clone();
            }
            Invoke(new Action<Bitmap>(ShowFrame), eventArgs.Frame.Clone());
        }
        catch (ObjectDisposedException)
        {
            // not sure, why....
        }
    }
    private void ShowFrame(Bitmap frame)
    {
        if (pictureBox1.Width < frame.Width)
        {
            pictureBox1.Width = frame.Width;
        }
        if (pictureBox1.Height < frame.Height)
        {
            pictureBox1.Height = frame.Height;
        }
        pictureBox1.Image = frame;
    }
    private void DecodeBarcode()
    {
        var reader = new BarcodeReader();
        while (true)
        {
            if (currentBitmapForDecoding != null)
            {
                var result = reader.Decode(currentBitmapForDecoding);
                if (result != null)
                {
                    Invoke(new Action<Result>(ShowResult), result);
                }
                currentBitmapForDecoding.Dispose();
                currentBitmapForDecoding = null;
            }
            Thread.Sleep(200);
        }
    }
    private void ShowResult(Result result)
    {
        currentResult = result;
        txtBarcodeFormat.Text = result.BarcodeFormat.ToString();
        txtContent.Text = result.Text;
    }
    private void button1_Click(object sender, EventArgs e)
    {
    }
}

}

cameradevice的类

  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using AForge.Video.DirectShow;

AForgeDemo

名称空间{

    internal class CameraDevices
    {
        public FilterInfoCollection Devices { get; private set; }
        public VideoCaptureDevice Current { get; private set; }
        public CameraDevices()
        {
            Devices = new FilterInfoCollection(FilterCategory.VideoInputDevice);
        }
        public void SelectCamera(int index)
        {
            if (index >= Devices.Count)
            {
                throw new ArgumentOutOfRangeException("index");
            }
            Current = new VideoCaptureDevice(Devices[index].MonikerString);
        }
    }
}

再次，我恳请任何人帮助我应该在按钮命令直接激活网络摄像头，而不是从组合框 中选择。

thanks a million

     // select the first available camera and start capturing
     camDevices.SelectCamera(0);
     camDevices.Current.NewFrame += Current_NewFrame;
     camDevices.Current.Start();