QR扫描程序ASP .NET Web应用程序未显示完整扫描数据

Question

我已将此代码改编为ASP .NET Web表单https://www.codeproject.com/Articles/75770/Basic-serial-port-listening-application

当我使用COM端口数据模拟器进行测试时，它可以正常工作，但是当我尝试真正的扫描仪时，它只显示使用特定QR码的最后一个单词，而其他单词则不显示任何内容。我让我在这里使用的代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO.Ports;
using System.IO;
using System.Text;
using System.Threading;

namespace Web_BarcodeScanner
{
    public partial class WFScanner : System.Web.UI.Page
    {
        SerialPortManager _spManager = new SerialPortManager();

        protected void Page_Load(object sender, EventArgs e)
        {
            //SerialSettings mySerialSettings = _spManager.CurrentSerialSettings;
            _spManager.CurrentSerialSettings.PortName = "COM5";
            _spManager.CurrentSerialSettings.BaudRate = 9600;
            _spManager.CurrentSerialSettings.DataBits = 8;
            _spManager.CurrentSerialSettings.Parity = Parity.None;
            _spManager.CurrentSerialSettings.StopBits = StopBits.One;

            _spManager.NewSerialDataRecieved += new EventHandler<SerialDataEventArgs>(_spManager_NewSerialDataRecieved);
        }


        private void _spManager_NewSerialDataRecieved(object sender, SerialDataEventArgs e)
        {
            // string str = System.Text.Encoding.Default.GetString(e.Data);           
            string str = Encoding.ASCII.GetString(e.Data);
            TextBox1.Text = str;
        }

        protected void btnStart_Click(object sender, EventArgs e)
        {

            _spManager.StartListening();
            Thread.Sleep(10000);

        }

        protected void btnClose_Click(object sender, EventArgs e)
        {
            _spManager.StopListening();


        }





    }
}

这是SerialPortManager类中的DataReceived方法：

private SerialPort _serialPort = new SerialPort();
public event EventHandler<SerialDataEventArgs> NewSerialDataRecieved;

.. .. .. ..

 void _serialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
    {

        int dataLength = _serialPort.BytesToRead;
        byte[] data = new byte[dataLength];
        int nbrDataRead = _serialPort.Read(data, 0, dataLength);
        if (nbrDataRead == 0)
            return;


        if (NewSerialDataRecieved != null)
            NewSerialDataRecieved(this, new SerialDataEventArgs(data));
    }