Question

I’m doing async network in C#.NET with the TcpClient and TcpListener classes.
I use WinForms for the GUI.

Whenever I receive data from a remote computer, the operation is done on a different underlying thread.

What I need to do is to update the GUI of my application whenever I receive a network response.

// this method is called whenever data is received
// it's async so it runs on a different thread
private void OnRead(IAsyncResult result)
{
    // update the GUI here, which runs on the main thread
    // (a direct modification of the GUI would throw a cross-thread GUI exception)
}

How can I achieve that?

Answer 1

In Winforms you need to use Control.Invoke Method (Delegate) to make sure that control is updated in the UI thread.

Example:

public static void PerformInvoke(Control ctrl, Action action)
{
    if (ctrl.InvokeRequired)
        ctrl.Invoke(action);
    else
        action();
}

Usage:

PerformInvoke(textBox1, () => { textBox1.Text = "test"; });