Pages 380 - 385, Defining Events. I can usually follow the code and figure out how things are connected. In the TRY IT OUT on page 381, I do not understand how MessageArrived in CheckForMessage method is null or not. Where in the program is MessageArrived set or not set? I've stepped through the program, used the immediate window to see where the value is but no luck. Again, where in the program is MessageArrived set to null or not, and how does the method determine this.

After putting the book down again for several hours I figured it out. In the Main method MessageArrived is set to myDisplay.DisplayMessage. So, while the program is running the value of MessageArrived never changes. It is never null. The only condition that changes during program running is the random value. I remmed out this line in Main to test this. My bad!