Do you want to see your button to be in pressed or unpressed state when you hit it once?

Did you catch that this behavior is not really button’s behavior – it is more checkBox’s behavior.

So to accomplish your goal you need move checkBox to your form and set appearance from “Normal” to “Button”. Like here:

System.Windows.Forms.CheckBox checkBox1 = new System.Windows.Forms.CheckBox();
checkBox1.Appearance = System.Windows.Forms.Appearance.Button;

Kick me if you don’t want to see such posts on my blog. :)