AE添加标注（Label Feature）

        private void AddlableTolayer(IFeatureLayer pFeatureLayer, string fieldname//shp中需要标注的字段)
        {
            IGeoFeatureLayer pGeoFeatureLayer = pFeatureLayer as IGeoFeatureLayer;
            pGeoFeatureLayer.DisplayAnnotation = true;//允许标注

            IFeatureClass pFeatureClass;
            pFeatureClass = pGeoFeatureLayer.FeatureClass;

            //矢量图层标注信息设置
            IAnnotateLayerPropertiesCollection pAnnotateLayerPropertiesCollection;
            pAnnotateLayerPropertiesCollection = pGeoFeatureLayer.AnnotationProperties;
            pAnnotateLayerPropertiesCollection.Clear();

            //定义一个矢量图层动态标注显示
            IAnnotateLayerProperties pAnnotateLayerProperties;

            //定义控制线标注的相对位置
            ILineLabelPosition pLineLabelPosition;

            //控制线标注的属性设置
            ILineLabelPlacementPriorities pLineLabelPlacementPriorities;
            IBasicOverposterLayerProperties pBasicOverposterLayerProperties;
            ILabelEngineLayerProperties pLabelEngineLayerProperties;           
           
            pLineLabelPosition = new LineLabelPositionClass();
            pLineLabelPosition.Parallel = false;//标注是否水平
            pLineLabelPosition.Perpendicular = true;//标注是否垂直

            pLineLabelPlacementPriorities = new LineLabelPlacementPrioritiesClass();
            pBasicOverposterLayerProperties = new BasicOverposterLayerPropertiesClass();
            pBasicOverposterLayerProperties.FeatureType = esriBasicOverposterFeatureType.esriOverposterPolyline;
            pBasicOverposterLayerProperties.LineLabelPlacementPriorities = pLineLabelPlacementPriorities;
            pBasicOverposterLayerProperties.LineLabelPosition = pLineLabelPosition;
           
            pLabelEngineLayerProperties = new LabelEngineLayerPropertiesClass();
            pLabelEngineLayerProperties.BasicOverposterLayerProperties = pBasicOverposterLayerProperties;
            pLabelEngineLayerProperties.Symbol.Size = 12;//字体大小
            pLabelEngineLayerProperties.Expression = "[" + fieldname + "]";//标注字段

            pAnnotateLayerProperties = pLabelEngineLayerProperties as IAnnotateLayerProperties;
            pAnnotateLayerPropertiesCollection.Add(pAnnotateLayerProperties);
        }