C#

public class login : System.Web.UI.Page <br />
   { <br />
      protected System.Web.UI.WebControls.TextBox txtUsername; <br />
      protected System.Web.UI.WebControls.TextBox txtPassword; <br />
      protected System.Web.UI.WebControls.Label lblCorrectLogin; <br />
      protected System.Web.UI.WebControls.LinkButton LinkButton1; <br />
      protected System.Web.UI.WebControls.Panel pnlLogIn; <br />
      protected System.Web.UI.WebControls.Label lblIsAuthenticated; <br />
<br />
    <br />
      private void Page_Load(object sender, System.EventArgs e) <br />
      { <br />
         if (! Page.IsPostBack) <br />
         { <br />
            if (Session["isAuthenticated"] == null) <br />
            { <br />
               this.lblIsAuthenticated.Text = "null"; <br />
            } <br />
            else <br />
            { <br />
               this.lblIsAuthenticated.Text = Session["isAuthenticated"].ToString(); <br />
            }       <br />
         } <br />
      } <br />
<br />
<br />
private void LinkButton1_Click(object sender, System.EventArgs e) <br />
      { <br />
         // Basic User Authentication, might want to replace with your own!!! <br />
         if (this.txtUsername.Text == "admin" && this.txtPassword.Text == "password") <br />
         { <br />
            // Set the Authentication Session Value <br />
            Session["isAuthenticated"] = true; <br />
<br />
            // Redirect to the Home Page <br />
            Response.Redirect ("hello.aspx"); <br />
         } <br />
         else <br />
         { <br />
            // Show error message informing of unmatching UserName and Password pair <br />
            this.lblCorrectLogin.Text = "Authentification Error!"; <br />
         } <br />
      } 

Line 31:             if (Session["isAuthenticated"] == null) <br />
Line 32:             { <br />
Line 33:                this.lblIsAuthenticated.Text = "null"; <br />
Line 34:             } <br />
Line 35:             else<br />
<br />
Source File: c:\inetpub\wwwroot\authentication\members.aspx.cs  Line: 33