iOS Question BarButton click event

I am making mt first iOS app and all is going well. However there is one thing that I do not find.
I need to have a menu button at the top of a page that when clicked shows a menu. I use this code to create the top right button:

Dim btn As BarButton
btn.InitializeBitmap(LoadBitmap(File.DirAssets, "menu.png"), "Button_Menu")

Dim btnList As List
btnList.Initialize
btnList.Set(0, btn)
MyPage.TopRightButtons = btnList

The icon is showing, but I was hoping to find the click event of that button under Button_Menu_Click but that does not work.
How can I use the click event?