public class CIMMaplexGeneralPlacementProperties : CIMGeneralPlacementProperties, System.ComponentModel.INotifyPropertyChanged, System.Xml.Serialization.IXmlSerializable  

// 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 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.
}

public static void CreateDictionary()
{
  //Get the map's defintion
  var mapDefn = MapView.Active.Map.GetDefinition();
  //Get the Map's Maplex labelling engine properties
  var mapDefnPlacementProps = mapDefn.GeneralPlacementProperties as CIMMaplexGeneralPlacementProperties;

  //Define the abbreaviations we need in an array            
  List<CIMMaplexDictionaryEntry> abbreviationDictionary = new List<CIMMaplexDictionaryEntry>
        {
            new CIMMaplexDictionaryEntry {
            Abbreviation = "Hts",
            Text = "Heights",
            MaplexAbbreviationType = MaplexAbbreviationType.Ending

         },
            new CIMMaplexDictionaryEntry
            {
                Abbreviation = "Ct",
                Text = "Text",
                MaplexAbbreviationType = MaplexAbbreviationType.Ending

            }
            //etc
        };
  //The Maplex Dictionary - can hold multiple Abbreviation collections
  var maplexDictionary = new List<CIMMaplexDictionary>
        {
            new CIMMaplexDictionary {
                Name = "NameEndingsAbbreviations",
                MaplexDictionary = abbreviationDictionary.ToArray()
            }

        };
  //Set the Maplex Label Engine Dictionary property to the Maplex Dictionary collection created above.
  mapDefnPlacementProps.Dictionaries = maplexDictionary.ToArray();
  //Set the Map defintion 
  MapView.Active.Map.SetDefinition(mapDefn);
}

private static void ApplyDictionary()
{
  var featureLayer = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>().First();

  QueuedTask.Run(() =>
  {
    //Creates Abbreviation dictionary and adds to Map Defintion                                
    CreateDictionary();
    //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 props to use abbreviation dictionary 
    CIMGeneralPlacementProperties labelEngine = MapView.Active.Map.GetDefinition().GeneralPlacementProperties;
    theLabelClass.MaplexLabelPlacementProperties.DictionaryName = "NameEndingsAbbreviations";
    theLabelClass.MaplexLabelPlacementProperties.CanAbbreviateLabel = true;
    theLabelClass.MaplexLabelPlacementProperties.CanStackLabel = false;
    //Set the labelClasses back
    lyrDefn.LabelClasses = listLabelClasses.ToArray();
    //set the layer's definition
    featureLayer.SetDefinition(lyrDefn);
  });
}

//Note: call within QueuedTask.Run()

//Get the active map's definition - CIMMap.
var cimMap = MapView.Active.Map.GetDefinition();
//Get the labeling engine from the map definition
var cimGeneralPlacement = cimMap.GeneralPlacementProperties;

if (cimGeneralPlacement is CIMMaplexGeneralPlacementProperties)
{
  //Current labeling engine is Maplex labeling engine
  //Create a new standard label engine properties
  var cimStandardPlacementProperties = new CIMStandardGeneralPlacementProperties();
  //Set the CIMMap's GeneralPlacementProperties to the new label engine
  cimMap.GeneralPlacementProperties = cimStandardPlacementProperties;
}
else
{
  //Current labeling engine is Standard labeling engine
  //Create a new Maplex label engine properties
  var cimMaplexGeneralPlacementProperties = new CIMMaplexGeneralPlacementProperties();
  //Set the CIMMap's GeneralPlacementProperties to the new label engine
  cimMap.GeneralPlacementProperties = cimMaplexGeneralPlacementProperties;
}
//Set the map's definition
MapView.Active.Map.SetDefinition(cimMap);

//Note: call within QueuedTask.Run()

//Get the active map's definition - CIMMap.
var cimMap = MapView.Active.Map.GetDefinition();
//Get the labeling engine from the map definition
var cimGeneralPlacement = cimMap.GeneralPlacementProperties;

if (cimGeneralPlacement is CIMMaplexGeneralPlacementProperties)
{
  //Current labeling engine is Maplex labeling engine
  //Create a new standard label engine properties
  var cimStandardPlacementProperties = new CIMStandardGeneralPlacementProperties();
  //Set the CIMMap's GeneralPlacementProperties to the new label engine
  cimMap.GeneralPlacementProperties = cimStandardPlacementProperties;
}
else
{
  //Current labeling engine is Standard labeling engine
  //Create a new Maplex label engine properties
  var cimMaplexGeneralPlacementProperties = new CIMMaplexGeneralPlacementProperties();
  //Set the CIMMap's GeneralPlacementProperties to the new label engine
  cimMap.GeneralPlacementProperties = cimMaplexGeneralPlacementProperties;
}
//Set the map's definition
MapView.Active.Map.SetDefinition(cimMap);