Import Master Page into another Master Page in ASP.NET

Question

Is it possible to make one master page simply include another master page?

I have three master pages, which have converged in content, and I want to make 2 of them point to the third, so that the content is not replicated, but leaving them in so that they can change easily in the future if they have to.

Answer 1

Yes, what you need is called nested master pages. Just set the MasterPageFile in the <%@ Master %> directive of child master pages to the parent one.

Main.Master:

<%@ Master Language="C#" %>

.... shared content ....
<asp:ContentPlaceHolder ID="C" runat="server" />

First.Master:

<% Master Language="C#" MasterPageFile="Main.Master" %>

<asp:Content runat="server" ContentPlaceHolderID="C">
   .... Some content ....
   <asp:ContentPlaceHolder ID="AnotherPlaceholder" runat="server" />
</asp:Content>

Second.Master:

<% Master Language="C#" MasterPageFile="Main.Master" %>

<asp:Content runat="server" ContentPlaceHolderID="C">
   .... Some other content ....
   <asp:ContentPlaceHolder ID="AnotherPlaceholder" runat="server" />
</asp:Content>