SetPreviousObservationsVisibility Method

In This Topic

Specifies whether to display previous observations or not.

Syntax

C#
Visual Basic (Declaration)

public void SetPreviousObservationsVisibility( 
   bool previousObservationsVisible
)

Public Sub SetPreviousObservationsVisibility( _
   ByVal previousObservationsVisible As Boolean _
)

Parameters

previousObservationsVisible: Indicates whether previous observations should be displayed.

Exceptions

Exception	Description
ArcGIS.Core.CalledOnWrongThreadException	This method or property must be called within the lambda passed to QueuedTask.Run.
System.InvalidOperationException	This feature layer does not support tracks.

Remarks

Non-track aware layers will throw a System.InvalidOperationException

Example

Check Previous Observation and Track Line Visibility

//The layer must be track aware and spatial for these settings
//to have an effect
if (streamLayer.TrackType != TrackType.Spatial)
  return;
//Must be on QueuedTask
if (!streamLayer.AreTrackLinesVisible)
  streamLayer.SetTrackLinesVisibility(true);
if (!streamLayer.ArePreviousObservationsVisible)
  streamLayer.SetPreviousObservationsVisibility(true);

Make Track Lines and Previous Observations Visible

//The layer must be track aware and spatial for these settings
//to have an effect
if (streamLayer.TrackType != TrackType.Spatial)
  return;

//Must be on QueuedTask

//Note: Setting PreviousObservationsCount larger than the 
//"SetExpirationMaxCount()" has no effect
streamLayer.SetPreviousObservationsCount(6);
if (!streamLayer.AreTrackLinesVisible)
  streamLayer.SetTrackLinesVisibility(true);
if (!streamLayer.ArePreviousObservationsVisible)
  streamLayer.SetPreviousObservationsVisibility(true);

Requirements

Target Platforms: Windows 11, Windows 10, Windows 8.1

Reference

FeatureLayer Class
FeatureLayer Members

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