I know how to use MasterType to access master page's public property? However, how do I access master page's master page's public property? I tried with Master.Master.PublicProperty, it tells me the type is defined in an assembly not referenced. Any thoughts?

Add the MasterType to the sub master page and point it to the base MasterPage. In your content page you set the MasterType to your sub master page (I suppose you know that).
You also need to add a reference from the content page to your base master page. You do that with .

Base Master Page:






Untitled Page

Base Maste page code:


public partial class MasterPage_master
{
public string Name
{
get { return "The Base Master Page"; }
}
}


Sub Master Page:











Content page:







Content page code:


public partial class Default2_aspx
{
void Page_Load()
{
Response.Write(Master.Master.Name);
}
}


Thanks so much. Reference tag is the key point here.

The Master property on the Page and MasterPage is typed; to make this strongly-typed we have a new directive called the MasterType:

<%@ mastertype virtualpath="~/mymaster.master" %.

you should be able to use this to enable strong-typing to public props exposed on the master

Hope this helps.