1using System;
 2using System.Data;
 3using System.Configuration;
 4using System.Collections;
 5using System.Web;
 6using System.Web.Security;
 7using System.Web.UI;
 8using System.Web.UI.WebControls;
 9using System.Web.UI.WebControls.WebParts;
10using System.Web.UI.HtmlControls;
11
12public partial class Controls_UserLogin : System.Web.UI.UserControl
13...{
14    protected void Page_Load(object sender, EventArgs e)
15    ...{
16        if (Session["User"] != null)
17        ...{
18            login.Style.Add("display", "none");
19            logout.Style.Add("display", "block");
20        }
21        else
22        ...{
23            login.Style.Add("display", "block");
24            logout.Style.Add("display", "none");
25        }
26    }
27
28
29    protected void Logout_Click(object sender, EventArgs e)
30    ...{
31        Session["User"] = null;
32        Response.Redirect("Logout.htm");
33    }
34}
35