AF SDK Reference

AFListData.EndOfStreamAsync Method

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AFListData.EndOfStreamAsync Method

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Last UpdatedNov 18, 2025
4 minute read

Returns an end-of-stream AFValue for each attribute in this list.

Namespace: OSIsoft.AF.Data
Assembly: OSIsoft.AFSDK (in OSIsoft.AFSDK.dll) Version: 3.1.1.1182

Syntax

public Task<IList<AFValue>> EndOfStreamAsync(
	CancellationToken cancellationToken = default
)

Public Function EndOfStreamAsync ( 
	Optional cancellationToken As CancellationToken = Nothing
) As Task(Of IList(Of AFValue))

Dim instance As AFListData
Dim cancellationToken As CancellationToken
Dim returnValue As Task(Of IList(Of AFValue))

returnValue = instance.EndOfStreamAsync(cancellationToken)

public:
Task<IList<AFValue^>^>^ EndOfStreamAsync(
	CancellationToken cancellationToken = CancellationToken()
)

member EndOfStreamAsync : 
        ?cancellationToken : CancellationToken 
(* Defaults:
        let _cancellationToken = defaultArg cancellationToken new CancellationToken()
*)
-> Task<IList<AFValue>>

Parameters

cancellationToken (Optional): Type: System.ThreadingCancellationToken
A cancellation token used to abort processing before completion. Passing the default CancellationToken.None will run to completion or until the PIConnectionInfo.OperationTimeOut period elapses.

Return Value

Type: TaskIListAFValue
Returns a task whose result is an AFValue list, one for each attribute in this list. If AFValue.IsGood returned by the data reference is , then the returned value is converted to the default UOM of the attribute and proper Type. The timestamp of the value will indicate the time of the recorded event. In the case of calculation based data references, it will normally indicate the closest input value's recorded value timestamp.

Exceptions

Exception	Condition
AggregateException	Asynchronous methods throw AggregateException on failure which will contain one or more exceptions containing the failure.

Remarks

The end of stream is the value with the largest or newest timestamp.

Notes to Callers
This method, property, or class is not available in the legacy .NET 3.5 version of the SDK.

Security Note
You must have ReadData security rights to read a data value.

Notes to Callers
This call might use a background task to complete some of its work. See the Threading Overview for some matters to consider when execution transitions to another thread.

Important
Asynchronous data calls on lists in AF SDK attempt to do as much work as possible asynchronously. Requested data access that cannot be performed asynchronously will fall back to synchronous calls so the entire list query is handled.

Important
Impersonation of AF SDK asynchronous calls relies on the .NET framework's built-in support for flowing execution context across asynchronous points. When making these calls while impersonating, the thread or runtime must be configured to propagate the impersonation across these asynchronous points (see the SecurityContext documentation for details).

Version Information

AFSDK

Supported in: 3.1.1, 3.1.0, 3.0.2, 3.0.1, 3.0.0, 2.10.11, 2.10.5, 2.10.0, 2.10, 2.9.5, 2.9, 2.8.5, 2.8

AF SDK Reference