Question

All I am trying to do is update a textBox (in this case txtInit) from another class. I have been reading a lot about how a UI Thread has to change itself, and something about using a dispatcher. I found an answer on here that seemed close, but I couldnt get it to work for me… it said to try using the line:

MainForm.Dispatcher.Invoke(new Action(delegate() {MainForm.myInstance.txtInit.Text = "Text"};);

In my ServerSide class, I need to send a String to the txtInit textbox on my MainForm.. and that is all I need to do.. thanks for any help.

Answer 1

Classes have nothing to do with threads(which is your problem right now).
Each Control has an Invoke method which will do the right thread synchronization for you.
So you can do

MainForm.myInstance.txtInit.Invoke((sender, args) => (sender as TextBox).Text = "text");

To improve performance you can test(which basically tells you if you’re in the same thread) the Control.IsInvokeRequired property.

Another way to do it is by using the SynchronizationContext of the UI thread which you need to capture in the constructor of the form from SynchronizationContext.Current and then do

syncContext.Send((obj) =>  MainForm.myInstance.txtInit.Text = "Text", null);