ArcGis 创建Annotation注记要素类、添加注记要素 并加载到Activeview AO C#

AO中一般有两种方式存储图面注记元素，一种使用TextElement，它是文档级的元素，编辑后要通过文档（mxd）保存；另一种是使用Annotation要素类，它是一个独立的要素类（featureclass），需要存储到地理数据库中。使用Annotation featureclass 的方式更灵活、更强大，至于如何灵活，如何强大，待你用到便自知。

1、创建一个标准的Annotation要素类（StandardAnnotationClass）

 

   public AnnotationMark(IFeatureClass outPolygonFc,string mdbPath,int referenceScale)
        {
            string annotationName = "Annotation";
            IWorkspaceFactory workspaceFactory = new AccessWorkspaceFactoryClass();
            IFeatureWorkspace featureWorkspace = workspaceFactory.OpenFromFile(mdbPath, 0) as IFeatureWorkspace;
            IGeoDataset geoDataset = outPolygonFc as IGeoDataset;
            ISpatialReference spatialReference = geoDataset.SpatialReference;
            Utils.UserWorkspace.FeatureWorkspace.TryDeleteFeatureClass(annotationName, featureWorkspace);
            featureClass = Utils.UserWorkspace.FeatureWorkspace.CreateStandardAnnotationClass(featureWorkspace, null,annotationName, spatialReference, referenceScale, esriUnits.esriMeters, null);
        }

下面是一个摘自Esri官网的代码段，可以使用它创建StandardAnnotationClass。

值得注意的是：
featureDataset根据数据库是否有数据集（dataset）而定，可以是null;
referenceScale是注记的参考比例，注记元素会以此为基准，放大或缩小，一般建议设置为出图比例尺，这样所设置的字号即出图字号。
configKeyword=""

 public static IFeatureClass CreateStandardAnnotationClass(IFeatureWorkspace featureWorkspace, IFeatureDataset featureDataset, String className,
ISpatialReference spatialReference, int referenceScale, esriUnits referenceScaleUnits, String configKeyword)
        {
            // Create an annotation class and provide it with a name.
            ILabelEngineLayerProperties labelEngineLayerProperties = new
                LabelEngineLayerPropertiesClass();
            IAnnotateLayerProperties annotateLayerProperties = (IAnnotateLayerProperties)
                labelEngineLayerProperties;
            annotateLayerProperties.Class = "Annotation";

            // Get the symbol from the annotation class. Make any changes to its properties
            // here.
            ITextSymbol annotationTextSymbol = labelEngineLayerProperties.Symbol;
            ISymbol annotationSymbol = (ISymbol)annotationTextSymbol;

            // Create a symbol collection and add the default symbol from the
            // annotation class to the collection. Assign the resulting symbol ID
            // to the annotation class.
            ISymbolCollection symbolCollection = new SymbolCollectionClass();
            ISymbolCollection2 symbolCollection2 = (ISymbolCollection2)symbolCollection;
            ISymbolIdentifier2 symbolIdentifier2 = null;
            symbolCollection2.AddSymbol(annotationSymbol, "Annotation", out
                symbolIdentifier2);
            labelEngineLayerProperties.SymbolID = symbolIdentifier2.ID;

            // Add the annotation class to a collection.
            IAnnotateLayerPropertiesCollection annotateLayerPropsCollection = new
                AnnotateLayerPropertiesCollectionClass();
            annotateLayerPropsCollection.Add(annotateLayerProperties);

            // Create a graphics layer scale object.
            IGraphicsLayerScale graphicsLayerScale = new GraphicsLayerScaleClass();
            graphicsLayerScale.ReferenceScale = referenceScale;
            graphicsLayerScale.Units = referenceScaleUnits;

            // Create the overposter properties for the standard label engine.
            IOverposterProperties overposterProperties = new BasicOverposterPropertiesClass();

            // Instantiate a class description object.
            IObjectClassDescription ocDescription = new
                AnnotationFeatureClassDescriptionClass();
            IFeatureClassDescription fcDescription = (IFeatureClassDescription)ocDescription;

            // Get the shape field from the class description's required fields.
            IFields requiredFields = ocDescription.RequiredFields;
            int shapeFieldIndex = requiredFields.FindField(fcDescription.ShapeFieldName);
            IField shapeField = requiredFields.get_Field(shapeFieldIndex);
            IGeometryDef geometryDef = shapeField.GeometryDef;
            IGeometryDefEdit geometryDefEdit = (IGeometryDefEdit)geometryDef;
            geometryDefEdit.SpatialReference_2 = spatialReference;

            // Create the annotation layer factory.
            IAnnotationLayerFactory annotationLayerFactory = new FDOGraphicsLayerFactoryClass();

            // Create the annotation feature class and an annotation layer for it.
            IAnnotationLayer annotationLayer = annotationLayerFactory.CreateAnnotationLayer
                (featureWorkspace, featureDataset, className, geometryDef, null,
                annotateLayerPropsCollection, graphicsLayerScale, symbolCollection, false,
                false, false, true, overposterProperties, configKeyword);

            // Get the feature class from the feature layer.
            IFeatureLayer featureLayer = (IFeatureLayer)annotationLayer;
            IFeatureClass featureClass = featureLayer.FeatureClass;

            return featureClass;
        }

 

2、创建Annotation要素（Annotation feature）

上面开始在AnnotationMark类的构造函数中创建了Annotation要素类featureClass，下面是创建Annotation 要素 feature的代码。

博主竟没有在墙内网络上找到相关的实现方案，只得爬墙去攒了这片代码，它主要是使用了ISymbolCollectionElement接口设置了Feature的各种属性。此外，网络上还有使用IFormattedTextSymbol接口的方案，博主并未测试，有需要可以戳下面链接：

Why do these annotations appear stacked/overlapping?（再羡国外论坛生态）

值得注意的是：
IGeometry pointGeometry 这个几何对象应该是一个IPoint;
esriTextHorizontalAlignment 与 esriTextVerticalAlignment指示这个point在Annotation元素（一个面Polygon）的哪个位置，借此确定放置位置。
ISymbolCollectionElement或者IFormattedTextSymbol还有更多的属性可以设置（本文不做补充），这些属性便是该要素记录各字段的值。

 public void CreateAnnotationFeature(IGeometry pointGeometry,string text,string fontName,double fontSize,esriTextHorizontalAlignment horizontalAlignment,
            esriTextVerticalAlignment verticalAlignment)
        {
            IFeature feature = featureClass.CreateFeature();

            ISymbolCollectionElement symbolCollectionElement = new TextElementClass();
            symbolCollectionElement.FontName = fontName;
            symbolCollectionElement.Size = fontSize;
            symbolCollectionElement.Text = text;
            symbolCollectionElement.HorizontalAlignment = horizontalAlignment;
            symbolCollectionElement.VerticalAlignment = verticalAlignment;
            symbolCollectionElement.Geometry = pointGeometry;

            IElement element = symbolCollectionElement as IElement;
            IAnnotationFeature2 annotationFeature2 = feature as IAnnotationFeature2;
            annotationFeature2.Annotation =element;
            annotationFeature2.Status = esriAnnotationStatus.esriAnnoStatusPlaced;
            feature.Store();
        }

3、要素类添加为图层

不啰嗦，上代码：

          IWorkspaceFactory workspaceFactory = new AccessWorkspaceFactoryClass();
            IFeatureWorkspace featureWorkspace = workspaceFactory.OpenFromFile(mdbPath, 0) as IFeatureWorkspace;
            IAnnotationLayerFactory annotationLayerFactory = new FDOGraphicsLayerFactoryClass();
            IAnnotationLayer annotationLayer = annotationLayerFactory.OpenAnnotationLayer(featureWorkspace, null, "Annotation");
            ILayer layer_Annotation = annotationLayer as ILayer;
            layer_Annotation.Name = tfh + "_Annotation";