how to hide/show a panel

sorry if this has been asked but i have a window that i would like to show on button press and hide again on the same button how do i do this?

 

Something like the following

Code (CSharp):

1. public GameObject panelObject;
2.  
3. button click event ...
4. {
5.   if (panelObject != null)
6.   {
7.     panel.SetActive(!panel.activeSelf);
8.   }
9.  
10. }