当Girdview的数据源为空时，也显示表头

 protected  void  GridViewDatabind()
    {
        DataTable dt  =  employer.GetPost();
         if  (dt !=   null )
        {
            GridView1.ShowHeader  =   true ;
             if  (dt.Rows.Count  ==   0 )
            {

                dt.Rows.Add(dt.NewRow());
                GridView1.DataSource  =  dt;
                GridView1.DataBind();
                GridView1.Rows[ 0 ].Visible  =   false ;
                GridView1.Rows[ 0 ].Cells.Clear();

            }
             else
            {
                GridView1.DataSource  =  dt;
                GridView1.DataBind();
            }

        }

    }