c# - Getting systemNullReference excepetion when changing menu item's title - Android -

i developing android app using c#, problem when changing menu item's title outside of button event, in oncreate method, getting systemnullreference excepetion able inside button click event without getting excepetion. want change item's title inside oncreate method directly when app starts, items title should changed. have far:

private imenu menu;     public override bool oncreateoptionsmenu(imenu menu)     {         this.menu = menu;         menuinflater.inflate(resource.menu.menu, menu);         return base.onprepareoptionsmenu(menu);     } protected override void oncreate(bundle bundle)     {         base.oncreate(bundle);         setcontentview(resource.layout.main);         button button = findviewbyid<button>(resource.id.button1);         button.click += delegate         {             imenuitem = menu.finditem(resource.id.about); // working on button click             about.settitle("about);          };         if (selected == "english") // selected string value saved in shared preference         {             imenuitem = menu.finditem(resource.id.about); // here getting systemnullreference excepetion             about.settitle("about);          }       } 

why having exception , how solve ? in advance..

move part of code:

 if (selected == "english") // selected string value saved in shared preference     {         imenuitem = menu.finditem(resource.id.about); // here getting systemnullreference excepetion         about.settitle("about);      } 

into end of oncreateoptionsmenu before return statement.

you should because init private imenu menu; value in oncreateoptionsmenu, called after oncreate(), , using private imenu menu; in oncreate, while not initialized far.