视觉工作室富文本框不显示文本

Question

I am using Visual studio 2017 and I have a RichTextBox that doesn't display text when I set it:

public void ArduinoDataRecived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{ 
    SerialPort TempSerial = (SerialPort)sender;
    ConsoleTextBox.AppendText(TempSerial.ReadLine());
}

The code runs with no errors and whenever I call the MessageBox.Show(ConsoleTextBox.text) it displays the text that the serial port sent and yet the text box doesn't display it.

If I have a completely different method that set the text then it works?

Answer 1

Probably a threading issue. Here's a copy-paste from the documentation :

The DataReceived event is raised on a secondary thread when data is received from the SerialPort object. Because this event is raised on a secondary thread, and not the main thread, attempting to modify some elements in the main thread, such as UI elements, could raise a threading exception. If it is necessary to modify elements in the main Form or Control, post change requests back using Invoke, which will do the work on the proper thread.

PS Before using System.IO.Ports.SerialPort be sure to read this . And this . Unfortunately, the problems are still not fixed in .NET 4.5.2. Not long ago I ported my serial comm code from C# to C++ to make my software work reliably for all users. But if it works on your machine, and you're not working on a commercial software, System.IO.Ports.SerialPort might still be fine for you.