But, this now leads to another error. When I exit the program, I get the following message:

"Object reference not set to an instance of an object", and the line pointed to is

this.SessionID = (int) listBox1.SelectedValue;

In the debugger's watch list, I can see that SessionID = 76, the last thing I processed. this.listBox1 seems to still exist. But, this.listBox1.SelectedValue is null.

Should I be cleaning up or something to prevent this? Or should I just check for SelectedValue not NULL before I try to use it?

Thanks
Jim