Form descends from Control, so it has an Invoke() method too.

Here's an application which changes the color of the main form from a
background thread, written for .NET 1.1. The background thread is
created when the form becomes visible for the first time. It sleeps for
a few seconds, and then triggers the change.

The invocation of the method which calls methods on the UI (i.e. the App
instance) has to be marshaled across to the UI thread. This is done by
creating a delegate which refers to the method which will be accessing
the UI, and passing this delegate to Control.Invoke. App descends from
Form, which ultimately descends from Control, so it has an Invoke method
too.

---8<---
using System;
using System.Windows.Forms;
using System.Threading;
using System.Drawing;

class App : Form
{
   static App _app;
   static Thread _backgroundThread;
   
   static void Main()
   {
       _app = new App();
       _app.VisibleChanged += new EventHandler(App_Shown);
       Application.Run(_app);
   }
   
   static void App_Shown(object sender, EventArgs e)
   {
       if (_backgroundThread == null && ((Form) sender).Visible)
       {
           _backgroundThread =
               new Thread(new ThreadStart(BackgroundThread));
           _backgroundThread.IsBackground = true;
           _backgroundThread.Start();
       }
   }
   
   static void BackgroundThread()
   {
       Thread.Sleep(TimeSpan.FromSeconds(3));
       _app.Invoke(new MethodInvoker(DoStuffOnUI));
   }
   
   static void DoStuffOnUI()
   {
       _app.BackColor = Color.Blue;
   }
}
--->8---

-- Barry