根据登陆用户，显示用户名

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class showSource : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //加载页面时判断用户是否登陆
        if (Session["stdXh"] == null || Session["stdXh"].ToString().Length == 0)
            Response.Redirect("Default.aspx");
        //如果已经登陆，显示学号信息
        labUser.Text = "学号为<b><font color=red>[" + Session["stdXh"].ToString() + "]</font></b>";
    }
}