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;
        }