This method returns a specified number of compressed values beginning at the requested start time in the direction specified.
OSIsoft.AFSDK (in OSIsoft.AFSDK.dll) Version: 18.104.22.1680
public Task<AFValues> RecordedValuesByCountAsync(
CancellationToken cancellationToken = null
Public Function RecordedValuesByCountAsync (
startTime As AFTime,
count As Integer,
forward As Boolean,
boundaryType As AFBoundaryType,
desiredUOM As UOM,
filterExpression As String,
includeFilteredValues As Boolean,
Optional cancellationToken As CancellationToken = Nothing
) As Task(Of AFValues)
Dim instance As AFData
Dim startTime As AFTime
Dim count As Integer
Dim forward As Boolean
Dim boundaryType As AFBoundaryType
Dim desiredUOM As UOM
Dim filterExpression As String
Dim includeFilteredValues As Boolean
Dim cancellationToken As CancellationToken
Dim returnValue As Task(Of AFValues)
returnValue = instance.RecordedValuesByCountAsync(startTime,
count, forward, boundaryType, desiredUOM,
CancellationToken cancellationToken = nullptr
member RecordedValuesByCountAsync :
startTime : AFTime *
count : int *
forward : bool *
boundaryType : AFBoundaryType *
desiredUOM : UOM *
filterExpression : string *
includeFilteredValues : bool *
?cancellationToken : CancellationToken
let _cancellationToken = defaultArg cancellationToken null
- Type: OSIsoft.AF.TimeAFTime
The start time of the request.
- Type: SystemInt32
The number of compressed values to return. This number must be greater than zero.
- Type: SystemBoolean
A value of indicates to begin at the start time and move forward in time. A value of
indicates to move backward in time. When moving backward, values will be returned in time descending order.
- Type: OSIsoft.AF.DataAFBoundaryType
A value from the AFBoundaryType enumeration that
determines how the time and value at the start time is determined.
- Type: OSIsoft.AF.UnitsOfMeasureUOM
The desired unit of measure for the returned values. If , then
the values are returned in the unit of measure specified by the associated attribute's
- Type: SystemString
A string containing a filter expression.
Expression variables are relative to the attribute.
Use '.' to reference the containing attribute.
A or empty string indicates no filtering.
If the attribute does not support the Filters
option, the filter will be ignored.
- Type: SystemBoolean
Specify to indicate that values which fail the filter
criteria are present in the returned data at the times where they occurred
with a value set to a "Filtered" enumeration value with bad status.
Repeated consecutive failures are omitted.
- 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.
Returns a task whose result is an AFValues
collection with the recorded values.
The data reference does not support the this method, or the configured data
reference does not support filter expressions and one was provided.
Asynchronous methods throw AggregateException on failure which will contain one or
more exceptions containing the failure.
| Notes to Callers|
This method, property, or class is only available in the .NET 4 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
for some matters to consider when execution transitions to another thread.
Asynchronous data calls in AF SDK attempt to do as much work as possible asynchronously. If no work can be done
asynchronously, then the SupportedDataMethods will report that asynchronous calls are not supported.
If an attribute uses a Formula or other calculated data reference has any input that supports asynchronous calls, then the attribute
will support asynchronous calls. When making an asynchronous data call, input data will be acquired asynchronously when possible
or synchronously otherwise. Data calls that require partitioning across versions will always fall back to synchronous calls.
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).
AFSDKSupported in: 2.10.5, 2.10, 2.9.5, 2.9, 2.8.5, 2.8