ArcObjects Library Reference (EditorExt)  

INetworkAnalysisExt.FeatureLayerCount Property

The number of feature layers currently loaded into the Network Analysis extension. 

[Visual Basic .NET]
Public ReadOnly Property FeatureLayerCount As Integer
[C#]
public int FeatureLayerCount {get;}

Product Availability

Available with ArcGIS Desktop.

Remarks

The Network Analysis Extension manages the feature layers for the current network. Only those feature layers added to the Extension are considered when the user interacts with the map, such as adding flags and barriers using the Flag and Barrier tools, displaying the flow arrows, and drawing the results of a trace task.
Feature layers are added to the Extension using the AddLayer method, and removed using the DropLayer method. The AddNetwork method does not explicitly add layers to the Extension.
In general, it is not necessary to manually add and drop layers from the Network Analysis Extension, as the Extension automatically performs this when a feature layer from the current network is added or deleted from the focus map of the document.

See Also

INetworkAnalysisExt Interface

.NET Samples

Custom upstream trace task (Code Files: CustomUpstreamTraceTaskVBNet)