include aspx file in other aspx file

[dawid_c]

\[code\]<% if (Session["desig"].ToString() == "Developer"){%> <td> <select name='zone' id="zone" onchange="showLoc(this.value,'mlodg_loc')"> <option value="http://stackoverflow.com/questions/14499965/Select Zone">Select Zone</option> <option value="http://stackoverflow.com/questions/14499965/East">East</option> <option value="http://stackoverflow.com/questions/14499965/West">West</option> <option value="http://stackoverflow.com/questions/14499965/North">North</option> <option value="http://stackoverflow.com/questions/14499965/South1">South1</option> <option value="http://stackoverflow.com/questions/14499965/South2">South2</option> <option value="http://stackoverflow.com/questions/14499965/South3">South3</option> </select> </td> <%} else {%> <td> <select name='zone' id="Select1" onchange="showLoc(this.value,'mlodg_loc')"> <option value="http://stackoverflow.com/questions/14499965/Select Zone">Select Zone</option> <option value="http://stackoverflow.com/questions/14499965/<%#Session["zone"]%>"><%# Session["zone"].ToString() %></option> </select> </td><%}%>\[/code\]the code above is working fine if I am writing it directly, I tried to write this code in other file and in main file i did \[code\]Response.WriteFile("zone.aspx")\[/code\]How can i include it is there any way to include and also would like to know a better way to write the above statements.Thankyou