How to execute code in the GUI Thread?

Question

I have a FileSystemWatcher that react on the Changed event.

I want to open the file, read its content display it in a textbox and hide the popup that has been create

Answer 1

The problem is that extendedNotifyIcon_OnHideWindow is being executed on a thread other than the UI thread. You will need to use the Dispatcher for that part as well. Also, I would not create a dedicated thread just to wait one second. You could easily refactor that part into a System.Threading.Timer. Here is my refactored version.

txtLog.Dispatcher.Invoke(
    (Action)(() =>
        {
            txtLog.Text = dataToDisplay;
            extendedNotifyIcon_OnShowWindow(); 
            new Timer(
                (state) =>
                {
                    button1.Dispatcher.BeginInvoke(
                        (Action)(() =>
                            {
                              extendedNotifyIcon_OnHideWindow(); 
                            }), null);
                }, null, 1000, Timeout.Infinite);
        }));