.net后台页面统一验证是否登录

using System;
using System.Collections.Generic;
using System.Web;

namespace DepartmentMIS.Web.myclass
{
  public class PageBase : System.Web.UI.Page
  {
    public PageBase()
    {
      this.Load += new EventHandler(BasePage_Load);
    }

    private void BasePage_Load(object sender, EventArgs e)
    {
      if (Session["UserNo"] == null || Session["UserNo"].ToString() == "")
      {
        Response.Redirect("~/Login.aspx");
      }
    }
  }
}

protected void btnLogin_Click(object sender, EventArgs e)
    {
      if (rblRole.SelectedValue == "1")
      {
        DataSet ds = AdminBLL.GetList("userName = '" + tbxUserName.Text.Trim() + "' and password = '" + tbxPassword.Text.Trim()+"' and isDeleted = 0");
        if (ds.Tables[0].Rows.Count == 1)
        {
          int id = Convert.ToInt32(ds.Tables[0].Rows[0]["id"]);
          Session["UserNo"] = ds.Tables[0].Rows[0]["id"];
          Session["UserName"] = ds.Tables[0].Rows[0]["userName"];
          Response.Redirect("admin/adminIndex.aspx");
        }
        else
        {
          Response.Write("<script>alert('用户名或密码错误！')</script>");
        }
      }
      if (rblRole.SelectedValue == "2")
      {
        DataSet ds = StuBLL.GetList("stuNo = '" + tbxUserName.Text.Trim() + "' and password = '" + tbxPassword.Text.Trim() + "' and isDeleted = 0");
        if (ds.Tables[0].Rows.Count == 1)
        {
          int id = Convert.ToInt32(ds.Tables[0].Rows[0]["id"]);
          Session["UserNo"] = ds.Tables[0].Rows[0]["id"];
          Session["UserName"] = ds.Tables[0].Rows[0]["stuName"];
          Response.Redirect("student/stusIndex.aspx");
        }
        else
        {
          Response.Write("<script>alert('用户名或密码错误！')</script>");
        }
      }

using System.Web.UI.WebControls.WebParts;
using System.Data.SqlClient;
using System.Collections;

namespace cbmis.ProDocumentMng
{
  public partial class DocumentList : BasePage //继承
  {
      protected void Page_Load(object sender, EventArgs e)
      {
    
      }

    }
  }
}