get information from popup menu without pushbotton GUI

Hello, I am developing a GUI and I want an input field to be blocked for one value of the popup menu (last one) so in the opening fcn I wrote

if true
popvalue=get(handles.popmenu,'Value');
if popvalue~=7  
  set(handles.edit,'enable','off')

end end

Right now when the program starts editbox is not available to edit . What I want to do (if possible), if the user changes the value of the popup menu I would like to capture that without a pushbotton. Change of the popup menu value will check and update the editbox status. Or I have to do this in two steps, like a pushbotton for enabling the editbox.

[Kamuran]

Nevermind I found the solution ...if anybody is interested

if true
  popvalue=get(handles.popmenu,'Value')
if popvalue~=7
set(handles.edit,'enable','off')
else
set(handles.edit''enable','on')
end
you put is in the callback function of popupmenu