ArcEngine中画出的Element遮挡地图的标注

ArcEngine中画出的Element遮挡地图的标注，解决：

                IGraphicsLayer pGraLayer = this.axMapControl1.ActiveView.FocusMap.BasicGraphicsLayer;
                IBarrierProperties pBarrierProp = pGraLayer as IBarrierProperties;
                pBarrierProp.Weight = (int)esriBasicOverposterWeight.esriMediumWeight;