protected void Page_Load(object sender, System.EventArgs e)
{
    pnl_question.Visible =false;
    //将panal中的按钮置为不能，以防误触发
    btn_submit.Enabled =false;
}

//找回密码之验证问题
private void btn_submit_Click(object sender, System.EventArgs e)
{
    tbx_uid.ReadOnly =true;
    if(tbx_answer.Text.ToString ()==Session["uanswer"].ToString())
    {
     lbl_message.Text ="您的密码是："+Session["upassword"].ToString ();
    }
    else
    { //将panel控件可见
     pnl_question.Visible =true;
     btn_submit.Enabled =true;
     lbl_message.Text ="您所回答的问题不正确，请重试！";
    } 
}

//找回密码
protected void tbx_uid_TextChanged(object sender, System.EventArgs e)
{ //从文件Web.config中读取连接字符串
    string strconn= ConfigurationSettings.AppSettings["dsn"];
    //连接本地计算机的MMS数据库
    SqlConnection cn= new SqlConnection (strconn);
    cn.Open ();
    //构造SQL语句，该语句在Users表中检查用户名和密码是否正确
    string mysql= "select * from Users where Uid='"+tbx_uid.Text +"'";
    //创建Command对象
    SqlCommand cm=new SqlCommand (mysql,cn);
    //执行ExecuteReader ()方法
    SqlDataReader dr=cm.ExecuteReader ();
    if(dr.Read ())
    { //将panel控件可见
     pnl_question.Visible =true;
     //保存当前用户名及用户权限
     tbx_question.Text =dr["uquestion"].ToString() ;
     //
     Session["uanswer"]=dr["uanswer"].ToString();
     Session["upassword"]=dr["upassword"].ToString() ;
     lbl_message.Text="请您按要求回答问题！";
     btn_submit.Enabled =true;
}
else
{
     lbl_message.Text ="对不起，输入的用户名有误，请重新输入";
}
}