ArcGIS Pro 2.7 API Reference Guide
UnclassedColorsRendererDefinition Class
Members  Example 

ArcGIS.Desktop.Mapping Namespace : UnclassedColorsRendererDefinition Class
Represents an unclassed colors renderer definition to show qualitative differences in feature values with an evenly distributed color scheme.
Object Model
UnclassedColorsRendererDefinition ClassCIMColorRamp ClassCIMSymbolReference ClassCIMSymbolReference Class
Syntax
public class UnclassedColorsRendererDefinition : RendererDefinition 
Public Class UnclassedColorsRendererDefinition 
   Inherits RendererDefinition
Remarks

Unclassed colors symbology is similar to graduated colors in that it's used to make choropleth maps.

Once you define an unclassed renderer, you can call a FeatureLayer's CreateRenderer and SetRenderer methods to create and assign a renderer to a feature layer.

Example
Create an unclassed renderer and set that to the selected feature layer of the active map.
string colorBrewerSchemesName = "ArcGIS Colors";
StyleProjectItem style = Project.Current.GetItems<StyleProjectItem>().First(s => s.Name == colorBrewerSchemesName);
string colorRampName = "Heat Map 4 - Semitransparent";
IList<ColorRampStyleItem> colorRampList = await QueuedTask.Run(() =>
{
  return style.SearchColorRamps(colorRampName);
});
ColorRampStyleItem colorRamp = colorRampList[0];

await QueuedTask.Run(() =>
{
  CIMPointSymbol pointSym = SymbolFactory.Instance.ConstructPointSymbol(ColorFactory.Instance.GreenRGB, 16.0, SimpleMarkerStyle.Diamond);
  CIMSymbolReference symbolPointTemplate = pointSym.MakeSymbolReference();

        //defining an unclassed renderer with custom upper and lower stops
        //all features with value >= 5,000,000 will be drawn with the upper color from the color ramp
        //all features with value <= 50,000 will be drawn with the lower color from the color ramp
        UnclassedColorsRendererDefinition unclassRndrDef = new UnclassedColorsRendererDefinition
                                    ("Population", symbolPointTemplate, colorRamp.ColorRamp, "Highest", "Lowest", 5000000, 50000)
  {

          //drawing features with null values with a different symbol
          ShowNullValues = true,
    NullValueLabel = "Unknown"
  };
  CIMPointSymbol nullSym = SymbolFactory.Instance.ConstructPointSymbol(ColorFactory.Instance.RedRGB, 16.0, SimpleMarkerStyle.Circle);
  unclassRndrDef.NullValueSymbol = nullSym.MakeSymbolReference();
  FeatureLayer flyr = MapView.Active.Map.Layers[0] as FeatureLayer;
  CIMClassBreaksRenderer cbRndr = (CIMClassBreaksRenderer)flyr.CreateRenderer(unclassRndrDef);
  flyr.SetRenderer(cbRndr);
});
Inheritance Hierarchy

System.Object
   ArcGIS.Desktop.Mapping.LayerDrawingDefinition
      ArcGIS.Desktop.Mapping.RendererDefinition
         ArcGIS.Desktop.Mapping.UnclassedColorsRendererDefinition

Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

UnclassedColorsRendererDefinition Members
ArcGIS.Desktop.Mapping Namespace