如何将通过串口发送的数据输出到textBox上？ C＃Visual Studio

Question

I'm currently working on a C# application and where I read Serial Data send through the USB port, where this data is to be shown on a textbox then eventually into a database. The code I have right now has it refresh to read serial data coming in every 2 seconds, but I cannot get the data onto the textBox. I'm fairly new to C# development so I am unsure as to what the best way to output my data onto a textbox or how to fix my problem in the first place. My code is below.

public partial class Form1 : Form
{
    SerialPort mySerialPort = new SerialPort("COM3");
    OleDbConnection connection = new OleDbConnection();
    public Form1()
    {
        InitializeComponent();
    }

    private void textBox1_TextChanged(object sender, EventArgs e)
    {

    }

    private void textBox2_TextChanged(object sender, EventArgs e)
    {

    }

    private void button2_Click(object sender, EventArgs e)
    {
        mySerialPort.BaudRate = 9600;
        mySerialPort.Parity = Parity.None;
        mySerialPort.StopBits = StopBits.One;
        mySerialPort.DataBits = 8;
        mySerialPort.Handshake = Handshake.None;
        mySerialPort.RtsEnable = true;

        mySerialPort.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);

        if (mySerialPort.IsOpen == false)
        {
            mySerialPort.Open();
        }
    }

    public void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
    {
        //gets data values from serial port
        SerialPort sp = (SerialPort)sender;
        string data = sp.ReadExisting();
        string time = GetTimestamp(DateTime.Now);

        int indata;
        long timeStamp;

        //parses strings to integers
        indata = Int32.Parse(data);
        timeStamp = Int64.Parse(time);


        //writes to console
        Console.WriteLine(indata);
        Console.WriteLine(timeStamp);

        //writes to text box
        textBox1.Text = data;

        Thread.Sleep(2000);
    }

    private void button3_Click(object sender, EventArgs e)
    {
        mySerialPort.Close();
    }

    private void label1_Click(object sender, EventArgs e)
    {

    }

    public static string GetTimestamp(DateTime value)
    {
        return value.ToString("yyyyMMddHHmmss");
    }

    private void label1_Click_1(object sender, EventArgs e)
    {

    }
}

Answer 1

The event DataReceived is handled with the method DataReceivedHandler on a different thread than the control textBox1 is created. So when running your program you should have get a System.InvalidOperationException . Which states exactly what I just described.

To get out of this dilemma you can use the Control.BeginInvoke method which would:

Execute the specified delegate asynchronously on the thread that the control's underlying handle was created on.

Basically it would drag the piece of code down to the thread that cretated the control. In this case the main thread. This is how you would use it:

//writes to text box
textBox1.BeginInvoke(new Action(() => { textBox1.Text = data; }));

I hope it helps.