C#串口通信问题

Question

我有一个小型 C# 应用程序的问题。该应用程序必须通过串行端口连接到读取数据矩阵代码的条形码扫描仪。 Data Matrix 代码表示一个字节数组，它是一个 zip 存档。我阅读了很多有关 SerialPort.DataReceived 工作方式的文章，但找不到解决问题的优雅方法。而且应用程序应该与不同的条形码扫描仪一起工作，所以我不能让它成为特定的扫描仪。这是我的一些代码:

    using System;
    using System.IO;
    using System.IO.Ports;
    using System.Windows.Forms;
    using Ionic.Zip;

    namespace SIUI_PE
    {
        public partial class Form1 : Form
        {
            SerialPort _serialPort;

        public Form1()
        {

            InitializeComponent();


        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                _serialPort = new SerialPort("COM1", 9600, Parity.None, 8, StopBits.One);
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error:" + ex.ToString());
                return;
            }
            _serialPort.Handshake = Handshake.None;
            _serialPort.ReadBufferSize = 10000;
            _serialPort.DataReceived += new SerialDataReceivedEventHandler(comPort_DataReceived);
            _serialPort.Open();

        }
        void comPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
           byte[] data = new byte[10000];
           _serialPort.Read(data, 0, 10000);
           File.WriteAllBytes(Directory.GetCurrentDirectory() + "/temp/fis.zip", data);
             try
             {
                 using (ZipFile zip = ZipFile.Read(Directory.GetCurrentDirectory() + "/temp/fis.zip"))
                 {
                     foreach (ZipEntry ZE in zip)
                     {
                         ZE.Extract(Directory.GetCurrentDirectory() + "/temp");
                     }
                 }
                 File.Delete(Directory.GetCurrentDirectory() + "/temp/fis.zip");

             }
             catch (Exception ex1)
             {
                 MessageBox.Show("Corrupt Archive: " + ex1.ToString());

             }
        }

    }
}

所以我的问题是:我怎么知道我读取了扫描器发送的所有字节？

Answer 1

我获得的用于读取条形码数据的代码，多年来在生产环境中一直完美运行，如下所示:

请注意，我的应用程序必须读取标准 UPC 条形码以及 GS1 DataBar，因此您可能不需要一些代码...

这里的重点是:

string ScanData = ScannerPort.ReadExisting(); 

它位于 DoScan 部分，只是将扫描数据作为字符串读取。它绕过了知道发送了多少字节的需要，并使其余代码更容易处理。

---

     // This snippet is in the Form_Load event, and it initializes teh scanner
        InitializeScanner();
        ScannerPort.ReadExisting();
        System.Threading.Thread.Sleep(1000);
     // ens snippet from Form_Load.

        this.ScannerPort.DataReceived += new SerialDataReceivedEventHandler(ScannerPort_DataReceived);


delegate void DoScanCallback();  // used for updating the form UI

void DoScan()
    {
        if (this.txtCouponCount.InvokeRequired)
        {
            DoScanCallback d = new DoScanCallback(DoScan);
            this.Invoke(d);
            return;
        }
        System.Threading.Thread.Sleep(100);
        string ScanData = ScannerPort.ReadExisting();
        if (isInScanMode)
        {
            try
            {
                HandleScanData(ScanData);
            }
            catch (Exception ex)
            {
                     System.Media.SystemSounds.Beep.Play();
                     MessageBox.Show("Invalid Scan");
            }
        }
    }
    void ScannerPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
    {
        // this call to sleep allows the scanner to receive the entire scan.
        // without this sleep, we've found that we get only a partial scan.
        try
        {
            DoScan();
        }
        catch (Exception ex)
        {
                System.Media.SystemSounds.Beep.Play();
                MessageBox.Show("Unable to handle scan event in ScannerPort_DataReceived." + System.Environment.NewLine + ex.ToString());
        }

    }
    void Port_ErrorReceived(object sender, System.IO.Ports.SerialErrorReceivedEventArgs e)
    {

          System.Media.SystemSounds.Beep.Play();
          MessageBox.Show(e.EventType.ToString());
    }
    private void HandleScanData(string ScanData)
    {
        //MessageBox.Show(ScanData + System.Environment.NewLine + ScanData.Length.ToString());

        //Determine which type of barcode has been scanned, and handle appropriately.
        if (ScanData.StartsWith("A") && ScanData.Length == 14)
        {
            try
            {
                ProcessUpcCoupon(ScanData);
            }
            catch (Exception ex)
            {
                     System.Media.SystemSounds.Beep.Play();
                     MessageBox.Show("Unable to process UPC coupon data" + System.Environment.NewLine + ex.ToString());

            }
        }
        else if (ScanData.StartsWith("8110"))
        {
            try
            {
                ProcessDataBarCoupon(ScanData);
            }
            catch (Exception ex)
            {
                     System.Media.SystemSounds.Beep.Play();
                     MessageBox.Show("Unable to process DataBar coupon data" + System.Environment.NewLine + ex.ToString());
            }
        }
        else
        {
                System.Media.SystemSounds.Beep.Play();
                MessageBox.Show("Invalid Scan" + System.Environment.NewLine + ScanData);
        }


    }


    private void InitializeScanner()
    {
        try
        {
            ScannerPort.PortName = Properties.Settings.Default.ScannerPort;
            ScannerPort.ReadBufferSize = Properties.Settings.Default.ScannerReadBufferSize;
            ScannerPort.Open();
            ScannerPort.BaudRate = Properties.Settings.Default.ScannerBaudRate;
            ScannerPort.DataBits = Properties.Settings.Default.ScannerDataBit;
            ScannerPort.StopBits = Properties.Settings.Default.ScannerStopBit;
            ScannerPort.Parity = Properties.Settings.Default.ScannerParity;
            ScannerPort.ReadTimeout = Properties.Settings.Default.ScannerReadTimeout;
            ScannerPort.DtrEnable = Properties.Settings.Default.ScannerDtrEnable;
            ScannerPort.RtsEnable = Properties.Settings.Default.ScannerRtsEnable;
        }
        catch (Exception ex)
        {
            MessageBox.Show("Unable to initialize scanner.  The error message received will be shown next.  You should close this program and try again.  If the problem persists, please contact support.", "Error initializing scanner");
            MessageBox.Show(ex.Message);
            Application.Exit();
        }


    }