c# - 使用串口显示体重秤的数据

Question

我是 COM PORT 的新手，我想从体重秤读取数据并以TextBox.
我能够获取数据，但它继续运行（流式传输）。
我只想在更改时显示。

我的代码：

using System.Linq;
using System.IO.Ports;

public partial class Form1 : Form
{
    private const int BaudRate = 9600;
    public Form1() { InitializeComponent(); }

    private void Form1_Load(object sender, EventArgs e)
    {
        string[] portNames = SerialPort.GetPortNames();     //<-- Reads all available comPorts
        foreach (var portName in portNames)
        {
            comboBox1.Items.Add(portName);                  //<-- Adds Ports to combobox
        }
        comboBox1.SelectedIndex = 0;                        //<-- Selects first entry (convenience purposes)
    }

    private void button1_Click(object sender, EventArgs e)
    {
        //<-- This block ensures that no exceptions happen
        if (_serialPort != null && _serialPort.IsOpen)
            _serialPort.Close();
        if (_serialPort != null)
            _serialPort.Dispose();
        //<-- End of Block

        _serialPort = new SerialPort(comboBox1.Text, BaudRate, Parity.None, 8, StopBits.One);       //<-- Creates new SerialPort using the name selected in the combobox
        _serialPort.DataReceived += SerialPortOnDataReceived;       //<-- this event happens everytime when new data is received by the ComPort
        _serialPort.Open();     //<-- make the comport listen
        textBox1.Text = "Listening on " + _serialPort.PortName + "...\r\n";

    }
    string str ="" ;
    private delegate void Closure();
    private void SerialPortOnDataReceived(object sender, SerialDataReceivedEventArgs serialDataReceivedEventArgs)
    {
        if (InvokeRequired)     //<-- Makes sure the function is invoked to work properly in the UI-Thread
            BeginInvoke(new Closure(() => { SerialPortOnDataReceived(sender, serialDataReceivedEventArgs); }));     //<-- Function invokes itself
        else
        {
            int dataLength = _serialPort.BytesToRead;
            byte[] data = new byte[dataLength];
            int nbrDataRead = _serialPort.Read(data, 0, dataLength);
            if (nbrDataRead == 0)
                return;
            str = System.Text.Encoding.UTF8.GetString(data);
            textBox1.Text = str.ToString();

            //_serialPort.Close(); 
            //var newVal = _serialPort.ReadExisting();
            //if (String.Compare(textBox1.Text, newVal) != 0.0)
            //    textBox1.Text = newVal;
        }
    }

    private void button2_Click(object sender, EventArgs e)
    {
        //_serialPort.Close();
        MessageBox.Show(str);
    }
}

标签： c#winforms