ArcGIS 开发的一个有关问题~SDE连接成功，图层却无法显示

        private void Form1_Load(object sender, EventArgs e)        {            OpenSDEWorkspace("xt-fumeizhi-01", "5151/tcp", "xt", "sa", "123", "sde.DEFAULT");            #region             //绑定要素到控件            m_mapControl = (IMapControl3)this.axMapControl1.Object;            m_pageLayoutControl = (IPageLayoutControl2)this.axPageLayoutControl1.Object;            //初始化controls synchronization calss            m_controlsSynchronizer = new            ControlsSynchronizer(m_mapControl, m_pageLayoutControl);                            //把MapControl和PageLayoutControl绑定起来(两个都指向同一个Map),然后设置MapControl为活动的Control            m_controlsSynchronizer.BindControls(true);            //为了在切换MapControl和PageLayoutControl视图同步，要添加Framework Control            m_controlsSynchronizer.AddFrameworkControl(axToolbarControl1.Object);            m_controlsSynchronizer.AddFrameworkControl(this.axTOCControl1.Object);            // 添加打开命令按钮到工具条            OpenNewMapDocument openMapDoc = new OpenNewMapDocument(m_controlsSynchronizer);            axToolbarControl1.AddItem(openMapDoc, -1, 0, false, -1, esriCommandStyles.esriCommandStyleIconOnly);#endregion        }        public IWorkspace OpenSDEWorkspace(string Server, string Instance, string Database, string User, string Password, string version)        {            IPropertySet pPropSet = new PropertySetClass();            IFeatureDataset pFeatureDataset;            //设置SDE连接属性信息            IWorkspaceFactory pSdeFact = new SdeWorkspaceFactoryClass();            pPropSet.SetProperty("SERVER", Server);            pPropSet.SetProperty("INSTANCE", Instance);            pPropSet.SetProperty("DATABASE", Database);            pPropSet.SetProperty("USER", User);            pPropSet.SetProperty("PASSWORD", Password);            pPropSet.SetProperty("VERSION", version);            try            {                //打开一个工作空间                pWorkspace = pSdeFact.Open(pPropSet, 0);                if (pWorkspace is IFeatureWorkspace)                {                    pFeatureWorkspace = pWorkspace as IFeatureWorkspace;                }                               //pFeatureWorkspace = pSdeFact.Open(pPropSet, 0) as IFeatureWorkspace;                //pFeatureDataset = pFeatureWorkspace.OpenFeatureDataset("cities.sdc");                pFeatureClass = pFeatureWorkspace.OpenFeatureClass("BOU1_4M_L");                pFeatureLayer = new FeatureLayerClass();                pFeatureLayer.FeatureClass = pFeatureClass;                pFeatureLayer.Name = pFeatureClass.AliasName;                //this.RenderLayer(pFeatureLayer);                //pMap = axMapControl1.Map;                axMapControl1.AddLayer(pFeatureLayer);                //pMap.AddLayer(pFeatureLayer);                axMapControl1.Refresh();                           }            catch (Exception ex)            {                MessageBox.Show("SDE Cann't Connection");            }            return pWorkspace;        }