ASP.NET Page does't show code behind code when clicking on Design code

[JerStype]

Page does't show code behind code when clicking on Design code and also code behind code display error as control not foundBelow code display error : System Error <%@Page Language="C#" AutoEventWireup="true" CodeFile="Register.aspx.cs" Inherits="Register" %>I don't why it fetches this type of error ,please help me It's URGENTDesign code :<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Register.aspx.cs" Inherits="Register" %>Code Behind: using System;