无法修改表达式，因为它不是变量

I'm trying to get an UserControl (which has a grid on it) on a Windows Form to resize. The below code is what I have in the Form. The behavior I'm getting is that the control is resized when I make it big. But it does not shrink. What am I doing wrong (or) What am I missing?I'm trying to get an UserControl (which has a g