C# - How To Change An Element On Screen Several Times In One Function

This has got to be easy, but has got me stumped.How do I change an element on screen several times in one function?I want to change a label to read something like "starting..." at the beginning of my function, then go away and do some stuff and then change the label to "finished" at the end.

errorMessage.Text = "Three...";
System.Threading.Thread.Sleep(1000);
errorMessage.Text = "Two...";
System.Threading.Thread.Sleep(1000);
errorMessage.Text = "One...";
System.Threading.Thread.Sleep(1000);
errorMessage.Text = "Go!";
System.Threading.Thread.Sleep(1000);