Class SymbolLayer

A base class to represent symbol layers, which are the fundamental components used to build multilayer symbols.

Inheritance

System.Object

SymbolLayer

FillSymbolLayer

MarkerSymbolLayer

StrokeSymbolLayer

Implements

System.ComponentModel.INotifyPropertyChanged

System.Object.ToString()

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

Namespace: Esri.ArcGISRuntime.Symbology

Assembly: Esri.ArcGISRuntime.dll

Syntax

public abstract class SymbolLayer : INotifyPropertyChanged

Remarks

The available symbol layer types correspond to the primitive geometry they are designed to render: marker layers for point, stroke layers for line, and fill layers for area or polygons. Layer types, however, are not applied exclusively to the corresponding geoelement geometry type. A marker symbol layer, for example, could be applied to a polyline feature to render its vertices. Each layer type has a unique set of properties to control its display. A symbol can contain one or several symbol layers of the same or different type. A symbol used to render polygons, for example, might contain a fill symbol layer to render the polygon interior, a stroke symbol layer for rendering the polygon outline, and a marker symbol layer to render polygon vertices. A symbol to render a polyline might contain several stroke layers of varying widths. If a symbol contains a layer that cannot render the type of geometry to which it is applied, that symbol layer is ignored when rendering.

The following table lists symbol types and symbol layers:

Symbol type	Typical symbol layers	Role
Point symbol	Marker layers	Draw relative to the point geometry
Polyline symbol	Marker layers	Draw at specified locations relative to the line geometry
Polyline symbol	Stroke layers	Draw relative to the line geometry
Polygon symbol	Marker layers	Draw relative to the polygon outline or in the interior, depending on placement setting
	Stroke layers	Draw relative to the polygon outline
	Fill layers	Draw relative to the polygon interior

Symbol and layer property interaction

Most SymbolLayer properties are only accessible on the symbol layer. There are some properties, however, that are also exposed for the symbol as a whole. Properties such as color and size, for example, can be modified either for an individual symbol layer, or for the symbol itself. For such properties, the value provided for the symbol may have an effect on the corresponding property for the symbol layers it contains. Similarly, the property value for a multilayer symbol might be determined from the values of the individual symbol layers it contains. There are no notifications from a symbol or symbol layer when a property has been changed. If your app needs to respond to property changes in a symbol (as a result of a propagated change, for example) you will need to reread property values to identify changes.

Unknown symbol layers or properties

The multilayer symbol specification is complex and continues to evolve. It is possible that some symbol layers (or properties) do not expose an API or are not known to the this API. In these cases the symbol will be handled as follows:

If a symbol can be rendered, but there is no public API, the base class for the appropriate symbol layer is returned in the layer collection.
The multilayer symbology specification for an existing symbol layer type may have been updated to include properties that are not recognized by this API. The symbol layer is created and rendered using the recognized properties. Any properties that cannot be identified are ignored.
In the event that a new (unrecognized) symbol layer is encountered, the symbol is ignored and is not added to the symbol layer collection.

Properties

Name	Description
IsColorLocked	Gets or sets a value indicating whether the symbol layer is color locked.
IsEnabled	Gets or sets a value indicating whether the symbol layer is enabled.

Events

Name	Description
PropertyChanged	Occurs when a property value changes.

Applies to

Target	Versions
.NET Standard 2.0	100.5 - 200.6
.NET	100.13 - 200.6
.NET Windows	100.13 - 200.6
.NET Android	200.0 - 200.6
.NET iOS	200.0 - 200.6
.NET Framework	100.5 - 200.6
Xamarin.Android	100.5 - 100.15
Xamarin.iOS	100.5 - 100.15
UWP	100.5 - 200.6