Add multiple admin and single user in ASP.Net using C#

Dear Sir,

I want to make multiple admin and single user.

I have four admin panel but i unable to define.

login. aspx

<%@ Page Title="" Language="C#" MasterPageFile="~/Site1.Master" AutoEventWireup="true" CodeBehind="Login.aspx.cs" Inherits="User_Login_CS.Login" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<asp:Login ID="Login1" runat="server" OnAuthenticate="ValidateUser">
</asp:Login>
<hr />
</asp:Content>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Web.Security;
using System.Configuration;

namespace User_Login_CS
{
    public partial class Login : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!this.IsPostBack)
            {
                if (this.Page.User.Identity.IsAuthenticated)
                {
                    FormsAuthentication.SignOut();
                    Response.Redirect("~/Login.aspx");
                }
            }
        }

        protected void ValidateUser(object sender, EventArgs e)
        {
            int userId = 0;
            string roles = string.Empty;
            string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
            using (SqlConnection con = new SqlConnection(constr))
            {
                using (SqlCommand cmd = new SqlCommand("Validate_User"))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.AddWithValue("@Username", Login1.UserName);
                    cmd.Parameters.AddWithValue("@Password", Login1.Password);
                    cmd.Connection = con;
                    con.Open();
                    SqlDataReader reader = cmd.ExecuteReader();
                    reader.Read();
                    userId = Convert.ToInt32(reader["UserId"]);
                    roles = reader["Roles"].ToString();
                    con.Close();
                }
                switch (userId)
                {
                    case -1:
                        Login1.FailureText = "Username and/or password is incorrect.";
                        break;
                    case -2:
                        Login1.FailureText = "Account has not been activated.";
                        break;
                    default:
                        FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(1, Login1.UserName, DateTime.Now, DateTime.Now.AddMinutes(2880), Login1.RememberMeSet, roles, FormsAuthentication.FormsCookiePath);
                        string hash = FormsAuthentication.Encrypt(ticket);
                        HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, hash);

                        if (ticket.IsPersistent)
                        {
                            cookie.Expires = ticket.Expiration;
                        }
                        Response.Cookies.Add(cookie);
                        Response.Redirect(FormsAuthentication.GetRedirectUrl(Login1.UserName, Login1.RememberMeSet));
                        break;
                }
            }
        }
    }
}