ArcEngine 分类标注

arcgis中可以在同一个图层中定义不同的标注方式。

在ArcgisEngine中实现起来如下（以按OID为条件区分为例）：

 /// <summary>        /// 标注特定图层        /// </summary>        /// <param name="IN_Layer">要标注的图层</param>        /// <param name="IN_AxmapControl">要标注的地图控件</param>        public void PUB_ShowTargetFeature(ILayer IN_Layer,AxMapControl IN_AxmapControl)        {            //设定地图标注引擎            IAnnotateMap Temp_AnnotateMap = new AnnotateMapClass();            IN_AxmapControl.Map.AnnotationEngine = Temp_AnnotateMap;            //获取GeoFeaturelayer            IGeoFeatureLayer Temp_AnnotationLayer = IN_Layer as IGeoFeatureLayer;            //标注集合            IAnnotateLayerPropertiesCollection Temp_AllAnnoProps;            Temp_AllAnnoProps = Temp_AnnotationLayer.AnnotationProperties;            Temp_AllAnnoProps.Clear();//清理已有标注属性            //定义两种标注类并添加            IAnnotateLayerProperties Temp_Anno1 = PRV_SetProperties(Temp_AnnotationLayer, PRV_SetSymbol(null, 8, "Arial"), IN_AxmapControl, "DefaultClass", " OBJECTID >100 ", "[Shape_Length]  & vbnewline &\"———\"  &vbnewline& [Shape_Area]");            Temp_AllAnnoProps.Add(Temp_Anno1);            IAnnotateLayerProperties Temp_Anno2 = PRV_SetProperties(Temp_AnnotationLayer, PRV_SetSymbol(null, 8, "Arial"), IN_AxmapControl, "Class1", " OBJECTID < 100 ", "[OBJECTID]");            Temp_AllAnnoProps.Add(Temp_Anno2);        }

下面是该函数的辅助函数：

        /// <summary>        /// 设定标注        /// </summary>        /// <param name="IN_FeatureLayer">要设定标注的图层</param>        /// <param name="IN_Symbol">标注表达式</param>        /// <param name="IN_AxmapControl">显示控件</param>        /// <param name="IN_ClassName">定义该种标注类型</param>        /// <param name="IN_ClassQuery">该种筛选方式</param>        /// <param name="IN_ClassExpression">标注表达式</param>        /// <returns>标注参数</returns>        private IAnnotateLayerProperties PRV_SetProperties(IFeatureLayer IN_FeatureLayer, ITextSymbol IN_Symbol, AxMapControl IN_AxmapControl, string IN_ClassName, string IN_ClassQuery, string IN_ClassExpression)        {            //标注表达式            ILabelEngineLayerProperties Temp_LabelEngine2 = new LabelEngineLayerPropertiesClass();            Temp_LabelEngine2.Expression = IN_ClassExpression;            //文字符号设定            Temp_LabelEngine2.Symbol = IN_Symbol;            //用来控制标注和要素的相对位置关系            ILineLabelPosition Temp_LineLpos = new LineLabelPositionClass();            Temp_LineLpos.Parallel = false;//修改标注的属性            Temp_LineLpos.Perpendicular = false;            Temp_LineLpos.InLine = true;            Temp_LineLpos.Above = false;            //用优先级来控制标注冲突            ILineLabelPlacementPriorities Temp_LinePlace = new LineLabelPlacementPrioritiesClass();            Temp_LinePlace.AboveStart = 1;            Temp_LinePlace.BelowAfter = 1;            //用来实现对ILineLabelPosition 和 ILineLabelPlacementPriorities以及更高级属性的控制            IBasicOverposterLayerProperties Temp_BasicOverPoster = new BasicOverposterLayerPropertiesClass();            Temp_BasicOverPoster.FeatureType = esriBasicOverposterFeatureType.esriOverposterPolygon;            Temp_BasicOverPoster.LineLabelPlacementPriorities = Temp_LinePlace;            Temp_BasicOverPoster.LineLabelPosition = Temp_LineLpos;            Temp_LabelEngine2.BasicOverposterLayerProperties = Temp_BasicOverPoster;            //设定标注            IMapOverposter Temp_MapPos = IN_AxmapControl.Map as IMapOverposter;            IOverposterProperties Temp_OverPoster = Temp_MapPos.OverposterProperties;            IAnnotateLayerProperties Temp_AnnoPClass = Temp_LabelEngine2 as IAnnotateLayerProperties;            //设定名称与筛选方式            Temp_AnnoPClass.Class = IN_ClassName;            Temp_AnnoPClass.WhereClause = IN_ClassQuery;            (IN_FeatureLayer as IGeoFeatureLayer).DisplayAnnotation = true;            return Temp_AnnoPClass;        }        /// <summary>        /// 设定标注符号        /// </summary>        /// <param name="IN_TextColor">字体颜色</param>        /// <param name="IN_TextSize">字体大小</param>        /// <param name="IN_FontName">字体名称</param>        /// <returns></returns>        private ITextSymbol PRV_SetSymbol(IRgbColor IN_TextColor,int IN_TextSize,string IN_FontName)        {            ITextSymbol Temp_TextSymbol = new TextSymbolClass(); ;            //文字颜色            if (IN_TextColor == null)            {                IN_TextColor = new RgbColorClass();                IN_TextColor.Red = 0;                IN_TextColor.Green = 0;                IN_TextColor.Blue = 0;                Temp_TextSymbol.Color = (IColor)IN_TextColor;            }            //文字字体与字号            Temp_TextSymbol.Size = IN_TextSize;            stdole.IFontDisp Temp_Font = new stdole.StdFontClass() as stdole.IFontDisp;            Temp_Font.Name = IN_FontName;            Temp_TextSymbol.Font = Temp_Font;            return Temp_TextSymbol;        }