//------------------------------
       //by:∮明天去要饭
       //-------------------------------       
        string listClass = Class.SelectedValue.ToString();
        dgManage.DataSource = BLL.NewsInfo.ListAllNews(listClass);
        try
        {
            dgManage.DataBind();
        }
        catch
        {
            if (dgManage.CurrentPageIndex > 0)
            {
                dgManage.CurrentPageIndex -= 1;
                dgManage.DataBind();
            }
        }