Include aspx file in another aspx file

Response.WriteFile

just writes files to the Http response stream without parsing it.

While it is possible to use "Server side" includes in asp.net ( <!--#include file="xxx.ext" -->

), it has the smell of classic asp code to it IMO.

The best way to get component reuse .aspx

is with User Control (.ascx) .

Similar question here

Update

Response.WriteFile

great for simple Html, .css or .js, but not for code containing C # or .Net object references (you used Session

in your code) like

Response.WriteFile("HtmlSnippet.html")

      

        
        
        
      

    

where HtmlSnippet.html

is

<p>In breaking news, scientists have discovered a planet in 
     <a href='http://en.wikipedia.org/wiki/Alpha_Centauri_Bb'>Alpha Centauri</a>
</p>

      

        
        
        
      

    

Server side use Include, eg. <!--#include file="file.inc" -->

will allow you to do something like this in your .inc file:

<% if (Session["desig"].ToString() == "Developer"){ %>
   You are a Developer!!
<% } %>

      

        
        
        
      

    

However, it is recommended that you use a custom control ( .ascx

), which allows you to do the same thing as the back end, but only in a much more reusable, object oriented, and testable way. Your reusable control will be a first class object with properties, methods, and the ability to raise events. You will need some research here.