如何正确绑定属性以形成事件？

I am doing a tutorial from the HeadFirst C# Book. The form itself WAS working before but now it isnt, and I dont remember what I changed. I've gone over the text several times now and it appears to be a verbatim copy, yet it doesnt work. What am I doing wrong? I imagine the problem must be in the Form.cs file.I am doing a tutorial from the HeadFirst C# Boo