SetExpirationMaxCount Method (StreamLayer)

In This Topic

Gets the expiration maximum feature count. This method must be called on the MCT. Use QueuedTask.Run.

Syntax

Visual Basic (Declaration)
C#

Public Sub SetExpirationMaxCount( _
   ByVal expirationMaxCount As ULong _
)

public void SetExpirationMaxCount( 
   ulong expirationMaxCount
)

Parameters

expirationMaxCount: The values indicating how many features will be stored at any given time.

Exceptions

Exception	Description
ArcGIS.Core.CalledOnWrongThreadException	This method or property must be called within the lambda passed to QueuedTask.Run.
System.InvalidOperationException	Stream service data connection is null.

Remarks

SetExpirationMethod must be set to ArcGIS.Core.CIM.FeatureExpirationMethod.MaximumFeatureCount or the maximum feature count is ignored. When FeatureLayer.IsTrackAware is true, ExpirationMaxCount represents the maximum number of features that will be stored per track. Otherwise, it represents the maximum number of features that will be stored period. The stream layer uses a FIFO method - the first observation in is the first one to be removed and so on. To prevent any features from being removed, set ExpirationMaxCount to 0.

When a stream layer is track-aware, use FeatureLayer.SetPreviousObservationsCount to set how many will be displayed on the map. Whereas SetExpirationMaxCount defines how many previous observation will be stored in memory.

Example

Set the Maximum Count of Previous Observations to be Stored in Memory

{
  // Note: call within QueuedTask.Run()
  {
    //Set Expiration Method and Max Expiration Count
    if (streamLayer.GetExpirationMethod() != FeatureExpirationMethod.MaximumFeatureCount)
      streamLayer.SetExpirationMethod(FeatureExpirationMethod.MaximumFeatureCount);
    streamLayer.SetExpirationMaxCount(15);
    //FYI
    if (streamLayer.IsTrackAware)
    {
      //MaxCount is per track! otherwise for the entire layer
    }
  }
}

Set the Maximum Age of Previous Observations to be Stored in Memory

{
  // Note: call within QueuedTask.Run()
  {
    //Set Expiration Method and Max Expiration Age
    if (streamLayer.GetExpirationMethod() != FeatureExpirationMethod.MaximumFeatureAge)
      streamLayer.SetExpirationMethod(FeatureExpirationMethod.MaximumFeatureAge);
    //set to 12 hours (max is 24 hours)
    streamLayer.SetExpirationMaxAge(new TimeSpan(12, 0, 0));

    //FYI
    if (streamLayer.IsTrackAware)
    {
      //MaxAge is per track! otherwise for the entire layer
    }
  }
}

Requirements

Target Platforms: Windows 11 Home, Pro, Enterprise (64 bit)

ArcGIS Pro version: 3.0 or higher.

Reference

StreamLayer Class
StreamLayer Members

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