I need help with C sharp Programming?

I'm still a beginner with this language and still learning, I just have a question. I am using Microsoft visual c sharp, its a small simple program that tells what color is made when you mix primary colors. There is also a clear button three checkboxes (red, blue, and yellow) a button and clear button and a lable for output
but what code do i use to uncheck the boxes with the clear button
thanks alot

For a windows form app
checkBox1.Checked = false;

For a WPF project
checkBox1.IsChecked = false;