Why is @MasterType directive not implied when setting @Page masterPageFIle?

Question

The docs for @MasterType have this example.

<%@ Page  masterPageFile="~/MasterPage.master"%>
<%@ MasterType  virtualPath="~/MasterPage.master"%> 

Why is @MasterType even needed? Couldn't the compiler automatically take the same actions based solely on @Page masterPageFile? When would you not want to use both?

Jentoft

+1 I've wondered that so many times myself! – Siobhan

Answer 1

You can set different master pages at each pages PreInit. So the master page is in general not well defined.

Pinchpenny

In this case I expect you wouldn't use either directive 'cause it's defined at runtime and you also wouldn't expect to get a typed Master property. The question is really directed towards situations where you do use the directives and the master page is known at compile time. – Jentoft

But there is only one situation. Page and master page are loosely coupled. You can change the master page at runtime. The MasterPage directive is just a smart cast for simple situations and you have to take the full responsibility for it. – Pinchpenny