Question

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/得到了一个例子，并成功地构建了它而没有错误。然而，当我连接我的网络摄像头运行它，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，网络摄像头将会打开。好吧，因为构建时没有错误，我无法确定出错的地方。我还看了一个项目，当用户按下按钮并打算将其实现到当前项目时，该项目会打开网络摄像头。我已经插入了按钮，但我不知道我应该在按钮上编程什么才能打开网络摄像头而不必选择组合框

有人会建议或引导我完成它。下面是主程序，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;

命名空间AForgeDemo { 公共部分类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);
        }
}

} protected override void 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的课程

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

命名空间AForgeDemo {

    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，我请求任何人帮助我将按钮命令直接激活网络摄像头，而不是从组合框中选择

感谢百万

Answer 1

按钮后面的事件处理程序所需的代码类似于方法cmbDevice_SelectedIndexChanged中的代码。我认为它应该如下所示

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

但我认为主要挑战是找出原始示例无法按预期工作的原因。如果在组合框的处理程序或按钮的处理程序中调用相同的代码，则没有区别。

需要帮助按钮来打开基于C＃的QR码项目的网络摄像头

1 个答案: