using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.Common;
using NewsModels;
using System.Data.SqlClient;
using NewsBLL;namespace Web.Admin
{
    public partial class AdminLogin : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {        }        protected void btnLogin_Click(object sender, EventArgs e)
        {
            if (Page.IsValid)
            {
                string loginName = txtLoginName.Text.Trim();
                string loginPwd = txtLoginPwd.Text.Trim();
                User user;
                if (UserManager.UserLogin(loginName, loginPwd, out user))
                {
                    if (user.Role == "2")
                    {
                        System.Web.Security.FormsAuthentication.SetAuthCookie(user.LoginName, false);
                        FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(1, user.LoginName, DateTime.Now, DateTime.Now.AddMinutes(30), false, "admin");
                        string hashticket = FormsAuthentication.Encrypt(ticket);
                        HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName,hashticket);
                        Response.Cookies.Add(cookie);
                        if (Request["ReturnUrl"] != null)
                        {
                            Response.Redirect(Request["ReturnUrl"]);
                        }
                        else
                        {
                        Response.Redirect("~/Admin/Default.aspx");
                        }
                    
                    }
                    else
                    {
                   Common.Message.RegScript(this,"你不是管理员,无权访问!");
                    }
                
                }
                else
                {
                 Common.Message.ReScript(this,"用户名或密码不正确,请重新输入!");
                }
            }
        } 
    }
}
提示Common未定义,请问在该在那层定义,里面该写些什么