Log out-ahould not able access all previous page.

 how can i do coding and where ,aspx file or .cs file for completle logout and not able to visite previous page.
I did this coding in aspx.cs file,but not work-->
protected override void Page_Load(object sender, EventArgs e)
    {
  
    
        FormsAuthentication.SignOut();
       Session.Clear();
        Session.Abandon();
        Response.Cookies.Clear();
      
    }
 
 
 
 
 
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