图层的自动标注

        /// <summary>
        /// 自动标注图层
        /// </summary>
        /// <param name="pGeoFlyr">矢量图层对象</param>
        /// <param name="pAutoLbl">动态标注对象</param>
        public void SetLayerAutoLabel(IGeoFeatureLayer pGeoFlyr)
        {
            try
            {
                if (pGeoFlyr == null)
                    return;
                IAnnotateLayerPropertiesCollection pAnnoProps = pGeoFlyr.AnnotationProperties;

                pAnnoProps.Clear();

                IAnnotateLayerProperties pAnnoLayerProps;
                ILineLabelPosition pPosition;
                ILineLabelPlacementPriorities pPlacement;
                IBasicOverposterLayerProperties pBasic;
                ILabelEngineLayerProperties pLabelEngine;

                ITextSymbol pTextSymbol = new TextSymbolClass();
                IRgbColor pColor = new RgbColorClass() { Red = 250, Blue = 0, Green = 0 };
                stdole.StdFont pFont = new StdFontClass();
                pFont.Name = "文鼎CS细等线";
                pFont.Size = 50;
                pTextSymbol.Font = pFont as stdole.IFontDisp;
                pTextSymbol.Color = pColor;

                pPosition = new LineLabelPositionClass();
                pPosition.Parallel  = true   ;
                pPosition.InLine = false ;
                pPosition.Perpendicular = false ;
                pPosition.Above = true;
                pPlacement = new LineLabelPlacementPrioritiesClass();
                pPlacement.AboveStart = 5;
                pPlacement.BelowAfter = 4;
                pBasic = new BasicOverposterLayerPropertiesClass();
                pBasic.FeatureType = esriBasicOverposterFeatureType.esriOverposterPolyline;
                pBasic.LineLabelPlacementPriorities = pPlacement;
                pBasic.LineLabelPosition = pPosition;
                pBasic.NumLabelsOption = esriBasicNumLabelsOption.esriOneLabelPerShape;

                pLabelEngine = new LabelEngineLayerPropertiesClass();
                pLabelEngine.Symbol = pTextSymbol;
                pLabelEngine.BasicOverposterLayerProperties = pBasic;
                string annoField = "[Shape_Length]";
                pLabelEngine.Expression = annoField;
                pAnnoLayerProps = pLabelEngine as IAnnotateLayerProperties;
                pAnnoLayerProps.LabelWhichFeatures = esriLabelWhichFeatures.esriSelectedFeatures;
                pAnnoLayerProps.WhereClause = "Shape_Length>40";
                pAnnoProps.Add(pAnnoLayerProps);
                pGeoFlyr.AnnotationProperties = pAnnoProps;
                pGeoFlyr.DisplayAnnotation = true;

            }
            catch (Exception Err)
            {
                MessageBox.Show(Err.Message, "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }
注意红色部分字段格式以及条件的书写方式