CIMLabelClass Class
In This Topic
Represents a label class which describes how to generate a set of text labels from a group of features in a feature layer.
Object Model
Syntax
Public Class CIMLabelClass Inherits CIMObject Implements System.ComponentModel.INotifyPropertyChanged, System.Xml.Serialization.IXmlSerializable
public class CIMLabelClass : CIMObject, System.ComponentModel.INotifyPropertyChanged, System.Xml.Serialization.IXmlSerializable
Example
Evaluating an Arcade Labeling Expression
{
string ArcadeLabelingExpressionName = "My Arcade Label Expression";
//Consult https://github.com/Esri/arcade-expressions/ and
//https://developers.arcgis.com/arcade/ for more examples
//and arcade reference
// Note: the following should be embedded in a QueuedTask.Run() statement
{
//Given a layer that has an arcade labeling
//expression and we evaluate it interactively...
var def = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label class
var label_class = def.LabelClasses
.FirstOrDefault(lc =>
{
return lc.Name == ArcadeLabelingExpressionName &&
lc.ExpressionEngine == LabelExpressionEngine.Arcade;
});
if (label_class == null)
return;
//evaluate the label expression against the features
var expr_info = new CIMExpressionInfo()
{
Expression = label_class.Expression,
ReturnType = ExpressionReturnType.String
};
//https://developers.arcgis.com/arcade/profiles/labeling/
using var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
expr_info, ArcadeProfile.Labeling);
//loop through the features
using var rc = featureLayer.Search();
while (rc.MoveNext())
{
var variables = new List<KeyValuePair<string, object>>() {
new("$feature", rc.Current)
};
var result = arcade.Evaluate(variables).GetResult();
//output
System.Diagnostics.Debug.WriteLine(
$"[{rc.Current.GetObjectID()}]: {result}");
}
}
}
Modify label expression using Arcade
{
// Note: the following should be embedded in a QueuedTask.Run() statement
{
//Get the layer's definition, using the community sample Data\Admin\AdminSample.aprx
if (featureLayer.GetDefinition() is not CIMFeatureLayer lyrDefn)
{
// not a feature layer, leave
return;
}
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//set the label class Expression to use the Arcade expression
theLabelClass.Expression = "return $feature.STATE_NAME + TextFormatting.NewLine + $feature.POP2000;";
//Set the label definition back to the layer.
featureLayer.SetDefinition(lyrDefn);
}
}
Creating a new Annotation Feature in an Annotation FeatureClass using a RowBuffer
{
// Must be called within QueuedTask.Run
void CreatingAnAnnotationFeature(Geodatabase geodatabase)
{
using (AnnotationFeatureClass annotationFeatureClass = geodatabase.OpenDataset<AnnotationFeatureClass>("Annotation // feature // class // name"))
using (AnnotationFeatureClassDefinition annotationFeatureClassDefinition = annotationFeatureClass.GetDefinition())
using (RowBuffer rowBuffer = annotationFeatureClass.CreateRowBuffer())
using (AnnotationFeature annotationFeature = annotationFeatureClass.CreateRow(rowBuffer))
{
annotationFeature.SetAnnotationClassID(0);
annotationFeature.SetStatus(AnnotationStatus.Placed);
// Get the annotation labels from the label collection
IReadOnlyList<CIMLabelClass> labelClasses =
annotationFeatureClassDefinition.GetLabelClassCollection();
// Setup the symbol reference with the symbol id and the text symbol
CIMSymbolReference cimSymbolReference = new CIMSymbolReference();
cimSymbolReference.Symbol = labelClasses[0].TextSymbol.Symbol;
cimSymbolReference.SymbolName = labelClasses[0].TextSymbol.SymbolName;
// Setup the text graphic
CIMTextGraphic cimTextGraphic = new CIMTextGraphic();
cimTextGraphic.Text = "Charlotte, North Carolina";
cimTextGraphic.Shape = new MapPointBuilderEx(new Coordinate2D(-80.843, 35.234), SpatialReferences.WGS84)
.ToGeometry();
cimTextGraphic.Symbol = cimSymbolReference;
// Set the symbol reference on the graphic and store
annotationFeature.SetGraphic(cimTextGraphic);
annotationFeature.Store();
}
}
}
Creating an annotation feature class
{
// Must be called within QueuedTask.Run
void CreateStandAloneAnnotationFeatureClass(
Geodatabase geodatabase, SpatialReference spatialReference)
{
// Creating a Cities annotation feature class
// with following user defined fields
// Name
// GlobalID
// Annotation feature class name
string annotationFeatureClassName = "CitiesAnnotation";
// Create user defined attribute fields for annotation feature class
FieldDescription globalIDFieldDescription = FieldDescription.CreateGlobalIDField();
FieldDescription nameFieldDescription = FieldDescription.CreateStringField("Name", 255);
// Create a list of all field descriptions
List<FieldDescription> fieldDescriptions = new List<FieldDescription>
{ globalIDFieldDescription, nameFieldDescription };
// Create a ShapeDescription object
ShapeDescription shapeDescription = new ShapeDescription(GeometryType.Polygon, spatialReference);
// Create general placement properties for Maplex engine
CIMMaplexGeneralPlacementProperties generalPlacementProperties =
new CIMMaplexGeneralPlacementProperties
{
AllowBorderOverlap = true,
PlacementQuality = MaplexQualityType.High,
DrawUnplacedLabels = true,
InvertedLabelTolerance = 1.0,
RotateLabelWithDisplay = true,
UnplacedLabelColor = new CIMRGBColor
{
R = 0,
G = 255,
B = 0,
Alpha = 0.5f // Green
}
};
// Create general placement properties for Standard engine
//CIMStandardGeneralPlacementProperties generalPlacementProperties =
// new CIMStandardGeneralPlacementProperties
// {
// DrawUnplacedLabels = true,
// InvertedLabelTolerance = 3.0,
// RotateLabelWithDisplay = true,
// UnplacedLabelColor = new CIMRGBColor
// {
// R = 255, G = 0, B = 0, Alpha = 0.5f // Red
// }
// };
// Create annotation label classes
// Green label
CIMLabelClass greenLabelClass = new CIMLabelClass
{
Name = "Green",
ExpressionTitle = "Expression-Green",
ExpressionEngine = LabelExpressionEngine.Arcade,
Expression = "$feature.OBJECTID",
ID = 1,
Priority = 0,
Visibility = true,
TextSymbol = new CIMSymbolReference
{
Symbol = new CIMTextSymbol()
{
Angle = 45,
FontType = FontType.Type1,
FontFamilyName = "Tahoma",
FontEffects = FontEffects.Normal,
HaloSize = 2.0,
Symbol = new CIMPolygonSymbol
{
SymbolLayers = new CIMSymbolLayer[]
{
new CIMSolidFill
{
Color = CIMColor.CreateRGBColor(0, 255, 0)
}
},
UseRealWorldSymbolSizes = true
}
},
MaxScale = 0,
MinScale = 0,
SymbolName = "TextSymbol-Green"
},
StandardLabelPlacementProperties = new CIMStandardLabelPlacementProperties
{
AllowOverlappingLabels = true,
LineOffset = 1.0
},
MaplexLabelPlacementProperties = new CIMMaplexLabelPlacementProperties
{
AlignLabelToLineDirection = true,
AvoidPolygonHoles = true
}
};
// Blue label
CIMLabelClass blueLabelClass = new CIMLabelClass
{
Name = "Blue",
ExpressionTitle = "Expression-Blue",
ExpressionEngine = LabelExpressionEngine.Arcade,
Expression = "$feature.OBJECTID",
ID = 2,
Priority = 0,
Visibility = true,
TextSymbol = new CIMSymbolReference
{
Symbol = new CIMTextSymbol()
{
Angle = 45,
FontType = FontType.Type1,
FontFamilyName = "Consolas",
FontEffects = FontEffects.Normal,
HaloSize = 2.0,
Symbol = new CIMPolygonSymbol
{
SymbolLayers = new CIMSymbolLayer[]
{
new CIMSolidFill
{
Color = CIMColor.CreateRGBColor(0, 0, 255)
}
},
UseRealWorldSymbolSizes = true
}
},
MaxScale = 0,
MinScale = 0,
SymbolName = "TextSymbol-Blue"
},
StandardLabelPlacementProperties = new CIMStandardLabelPlacementProperties
{
AllowOverlappingLabels = true,
LineOffset = 1.0
},
MaplexLabelPlacementProperties = new CIMMaplexLabelPlacementProperties
{
AlignLabelToLineDirection = true,
AvoidPolygonHoles = true
}
};
// Create a list of labels
List<CIMLabelClass> labelClasses = new List<CIMLabelClass> { greenLabelClass, blueLabelClass };
// Create an annotation feature class description object to describe the feature class to create
AnnotationFeatureClassDescription annotationFeatureClassDescription =
new AnnotationFeatureClassDescription(annotationFeatureClassName, fieldDescriptions, shapeDescription,
generalPlacementProperties, labelClasses)
{
IsAutoCreate = true,
IsSymbolIDRequired = false,
IsUpdatedOnShapeChange = true
};
// Create a SchemaBuilder object
SchemaBuilder schemaBuilder = new SchemaBuilder(geodatabase);
// Add the creation of the Cities annotation feature class to the list of DDL tasks
schemaBuilder.Create(annotationFeatureClassDescription);
// Execute the DDL
bool success = schemaBuilder.Build();
// Inspect error messages
if (!success)
{
IReadOnlyList<string> errorMessages = schemaBuilder.ErrorMessages;
//etc.
}
}
}
Creating a feature-linked annotation feature class
{
// Must be called within QueuedTask.Run
void CreateFeatureLinkedAnnotationFeatureClass(Geodatabase geodatabase,
SpatialReference spatialReference)
{
// Creating a feature-linked annotation feature class between water pipe and valve in water distribution network
// with following user defined fields
// PipeName
// GlobalID
// Annotation feature class name
string annotationFeatureClassName = "WaterPipeAnnotation";
// Create user defined attribute fields for annotation feature class
FieldDescription pipeGlobalID = FieldDescription.CreateGlobalIDField();
FieldDescription nameFieldDescription = FieldDescription.CreateStringField("Name", 255);
// Create a list of all field descriptions
List<FieldDescription> fieldDescriptions = new List<FieldDescription>
{ pipeGlobalID, nameFieldDescription };
// Create a ShapeDescription object
ShapeDescription shapeDescription = new ShapeDescription(GeometryType.Polygon, spatialReference);
// Create general placement properties for Maplex engine
CIMMaplexGeneralPlacementProperties generalPlacementProperties = new CIMMaplexGeneralPlacementProperties
{
AllowBorderOverlap = true,
PlacementQuality = MaplexQualityType.High,
DrawUnplacedLabels = true,
InvertedLabelTolerance = 1.0,
RotateLabelWithDisplay = true,
UnplacedLabelColor = new CIMRGBColor
{
R = 255,
G = 0,
B = 0,
Alpha = 0.5f
}
};
// Create annotation label classes
// Green label
CIMLabelClass greenLabelClass = new CIMLabelClass
{
Name = "Green",
ExpressionTitle = "Expression-Green",
ExpressionEngine = LabelExpressionEngine.Arcade,
Expression = "$feature.OBJECTID",
ID = 1,
Priority = 0,
Visibility = true,
TextSymbol = new CIMSymbolReference
{
Symbol = new CIMTextSymbol()
{
Angle = 45,
FontType = FontType.Type1,
FontFamilyName = "Tahoma",
FontEffects = FontEffects.Normal,
HaloSize = 2.0,
Symbol = new CIMPolygonSymbol
{
SymbolLayers = new CIMSymbolLayer[]
{
new CIMSolidFill
{
Color = CIMColor.CreateRGBColor(0, 255, 0)
}
},
UseRealWorldSymbolSizes = true
}
},
MaxScale = 0,
MinScale = 0,
SymbolName = "TextSymbol-Green"
},
StandardLabelPlacementProperties = new CIMStandardLabelPlacementProperties
{
AllowOverlappingLabels = true,
LineOffset = 1.0
},
MaplexLabelPlacementProperties = new CIMMaplexLabelPlacementProperties
{
AlignLabelToLineDirection = true,
AvoidPolygonHoles = true
}
};
// Blue label
CIMLabelClass blueLabelClass = new CIMLabelClass
{
Name = "Blue",
ExpressionTitle = "Expression-Blue",
ExpressionEngine = LabelExpressionEngine.Arcade,
Expression = "$feature.OBJECTID",
ID = 2,
Priority = 0,
Visibility = true,
TextSymbol = new CIMSymbolReference
{
Symbol = new CIMTextSymbol()
{
Angle = 45,
FontType = FontType.Type1,
FontFamilyName = "Consolas",
FontEffects = FontEffects.Normal,
HaloSize = 2.0,
Symbol = new CIMPolygonSymbol
{
SymbolLayers = new CIMSymbolLayer[]
{
new CIMSolidFill
{
Color = CIMColor.CreateRGBColor(0, 0, 255)
}
},
UseRealWorldSymbolSizes = true
}
},
MaxScale = 0,
MinScale = 0,
SymbolName = "TextSymbol-Blue"
},
StandardLabelPlacementProperties = new CIMStandardLabelPlacementProperties
{
AllowOverlappingLabels = true,
LineOffset = 1.0
},
MaplexLabelPlacementProperties = new CIMMaplexLabelPlacementProperties
{
AlignLabelToLineDirection = true,
AvoidPolygonHoles = true
}
};
// Create a list of labels
List<CIMLabelClass> labelClasses = new List<CIMLabelClass> { greenLabelClass, blueLabelClass };
// Create linked feature description
// Linked feature class name
string linkedFeatureClassName = "WaterPipe";
// Create fields for water pipe
FieldDescription waterPipeGlobalID = FieldDescription.CreateGlobalIDField();
FieldDescription pipeName = FieldDescription.CreateStringField("PipeName", 255);
// Create a list of water pipe field descriptions
List<FieldDescription> pipeFieldDescriptions = new List<FieldDescription> { waterPipeGlobalID, pipeName };
// Create a linked feature class description
FeatureClassDescription linkedFeatureClassDescription = new FeatureClassDescription(linkedFeatureClassName,
pipeFieldDescriptions,
new ShapeDescription(GeometryType.Polyline, spatialReference));
// Create a SchemaBuilder object
SchemaBuilder schemaBuilder = new SchemaBuilder(geodatabase);
// Add the creation of the linked feature class to the list of DDL tasks
FeatureClassToken linkedFeatureClassToken = schemaBuilder.Create(linkedFeatureClassDescription);
// Create an annotation feature class description object to describe the feature class to create
AnnotationFeatureClassDescription annotationFeatureClassDescription =
new AnnotationFeatureClassDescription(annotationFeatureClassName, fieldDescriptions, shapeDescription,
generalPlacementProperties, labelClasses, new FeatureClassDescription(linkedFeatureClassToken))
{
IsAutoCreate = true,
IsSymbolIDRequired = false,
IsUpdatedOnShapeChange = true
};
// Add the creation of the annotation feature class to the list of DDL tasks
schemaBuilder.Create(annotationFeatureClassDescription);
// Execute the DDL
bool success = schemaBuilder.Build();
// Inspect error messages
if (!success)
{
IReadOnlyList<string> errorMessages = schemaBuilder.ErrorMessages;
//etc.
}
}
}
Apply text symbol to a feature layer
{
// Note: call within QueuedTask.Run()
{
//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//Set the label classes' symbol to the custom text symbol
//Refer to the ProSnippets-TextSymbols wiki page for help with creating custom text symbols.
//Example: var textSymbol = await CreateTextSymbolWithHaloAsync();
theLabelClass.TextSymbol.Symbol = textSymbol;
lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition
//set the label's visibility
featureLayer.SetLabelVisibility(true);
}
}
Modify the Placement/Position of labels - Point geometry
{
// Note: call within QueuedTask.Run()
{
//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//Modify label Placement
//Check if the label engine is Maplex or standard.
CIMGeneralPlacementProperties labelEngine =
MapView.Active.Map.GetDefinition().GeneralPlacementProperties;
if (labelEngine is CIMStandardGeneralPlacementProperties) //Current labeling engine is Standard labeling engine
theLabelClass.StandardLabelPlacementProperties.PointPlacementMethod =
StandardPointPlacementMethod.OnTopPoint;
else //Current labeling engine is Maplex labeling engine
theLabelClass.MaplexLabelPlacementProperties.PointPlacementMethod =
MaplexPointPlacementMethod.CenteredOnPoint;
lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition
}
}
How to apply a Text Symbol to label of a layer
{
var cimMap = MapView.Active.Map.GetDefinition();
CIMTextSymbol simpleTextSymbol = SymbolFactory.Instance.ConstructTextSymbol(ColorFactory.Instance.GreenRGB, 8.5, "Corbel", "Regular");
var lyrDefn = theLayerToLabel.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//Place all labels horizontally
theLabelClass.StandardLabelPlacementProperties.LineLabelPosition.Horizontal = true;
//theLabelClass.MaplexLabelPlacementProperties.AlignLabelToLineDirection = true;
//Set the label classes' symbol to the custom text symbol
theLabelClass.TextSymbol.Symbol = simpleTextSymbol;
lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
theLayerToLabel.SetDefinition(lyrDefn);
(theLayerToLabel as FeatureLayer).SetLabelVisibility(true);
}
Inheritance Hierarchy
System.Object
ArcGIS.Core.CIM.CIMObject
ArcGIS.Core.CIM.CIMLabelClass
Requirements
Target Platforms: Windows 11 Home, Pro, Enterprise (64 bit)
ArcGIS Pro version: 3.0 or higher.
See Also