SetPreviousObservationsCount Method

In This Topic

Specifies the maximum number of previous observations to be displayed for each track.

Syntax

Visual Basic (Declaration)
C#

Public Sub SetPreviousObservationsCount( _
   ByVal previousObservationsCount As Integer _
)

public void SetPreviousObservationsCount( 
   int previousObservationsCount
)

Parameters

previousObservationsCount: The number of maximum previous observations to display for each track.

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

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)
  {
    // not track aware and spatial
  }

  // Note: call within QueuedTask.Run()
  {
    //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 Home, Pro, Enterprise (64 bit)

ArcGIS Pro version: 3.0 or higher.

Reference

FeatureLayer Class
FeatureLayer Members

Send feedback