iOS Question How to add the Page_Resize to new code Module

I open the visual Designer, and click the File -> ColorsLayout
in the Abstract Designer
I click the mouse right button,chiose Generate-> Resize
in ColorsModule
Sub Page1_Resize (Width As Float, Height As Float)

End Sub
add it auto
And I add Msgbox("resize","pg") in the sub,like this
Sub Page1_Resize (Width As Float, Height As Float)
Msgbox("resize","pg")
End Sub
when I run it ,the event is not response

Help me
what's wrong with me?
thanks
I want add the Resize event in the ColorsModule.