Comments by demu97 (Top 2 by date)

the problem is that when I try to change the text on textbox using the method invoke the window crash or work very slow.
textBox1.Invoke((MethodInvoker)(() => textBox1.Text = serialPort1.ReadLine()));

but if i delete the method invoke (thus not changing the textbox but just reading from serial port) it work correctly.

so I thinck that problem is change text box value