protected void btnChangePwd_Click(object sender, EventArgs e)
        {
            SysAdmin user = new SysAdmin();

            user = (SysAdmin)Session["Currentuser"];
            string newpwd = txtNewPwd.Text.Trim();
            string oldpwd = txtOldPwd.Text.Trim();

            try
            {
                if (user.LoginPwd != oldpwd)
                {
                    ltaMsg.Text = "<script>alert('原密码错误!')</script>";
                }
                else
                {
                    AdminServices.ChangePwd(user, newpwd);
                    Session["Currentuser"] = user;
                    ltaMsg.Text            = "<script>alert('修改成功!');location='../Default.aspx'</script>";
                }
            }
            catch (Exception ex)
            {
                ltaMsg.Text = "<script>alert('" + ex.Message + "')</script>";
                throw ex;
            }
        }