Acceptin User Control variable

I want to send public variable values to from webuser control to .aspx page
for this i take referece in .aspx
like
<%@ Reference Control ="~/LocationAutoFill.ascx" %>
and in my .cs file
LocationAutoFill UC = (LocationAutoFill)Page.FindControl("LocationAutoFill.ascx");
But wile accepting variale value it showing error object reference not set to instance of object
-Prashanth