.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)      {          }    }  }}