datagrid绑定list没有数据 表头不显示的解决方法

　　var list = Pt_OrderWorkFlow_DAO.GetOrderWorkFlow(wfid, uid, 1);

　　if (list == null)

　　{

　　list = new List<Pt_OrderWorkFlow>();

　　}

　　dgWaitList.DataSource = list;

　　dgWaitList.DataBind();

　　OADataContext db = DatabaseHelper.GetDB();

　　var rs = (from a in db.Pt_OrderWorkFlow

　　where a.WFID == wfID && a.ContractNumber == cNumber

　　select a).ToList<Pt_OrderWorkFlow>();

　　return rs.Count() > 0 ? rs : new List<Pt_OrderWorkFlow>();