AF SDK Reference

AFSearch.HistogramAsync(TBin) Method

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AFSearch.HistogramAsync(TBin) Method

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Last UpdatedNov 18, 2025
4 minute read

Generates a histogram using the specified weighting for items matching this search asynchronously.

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

Syntax

public Task<AFBinnedResult<TBin>> HistogramAsync<TBin>(
	string field,
	IEnumerable<TBin> bins,
	UOM binUOM,
	CancellationToken cancellationToken
)
where TBin : Object, IComparable<TBin>

Public Function HistogramAsync(Of TBin As {Object, IComparable(Of TBin)}) ( 
	field As String,
	bins As IEnumerable(Of TBin),
	binUOM As UOM,
	cancellationToken As CancellationToken
) As Task(Of AFBinnedResult(Of TBin))

Dim instance As AFSearch
Dim field As String
Dim bins As IEnumerable(Of TBin)
Dim binUOM As UOM
Dim cancellationToken As CancellationToken
Dim returnValue As Task(Of AFBinnedResult(Of TBin))

returnValue = instance.HistogramAsync(field, 
	bins, binUOM, cancellationToken)

public:
generic<typename TBin>
where TBin : Object, IComparable<TBin>
Task<AFBinnedResult<TBin>^>^ HistogramAsync(
	String^ field, 
	IEnumerable<TBin>^ bins, 
	UOM^ binUOM, 
	CancellationToken cancellationToken
)

member HistogramAsync : 
        field : string * 
        bins : IEnumerable<'TBin> * 
        binUOM : UOM * 
        cancellationToken : CancellationToken -> Task<AFBinnedResult<'TBin>>  when 'TBin : Object and IComparable<'TBin>

Parameters

field: Type: SystemString
The field whose value should be binned.
bins: Type: System.Collections.GenericIEnumerableTBin
The bins the field should be sorted into.
binUOM: Type: OSIsoft.AF.UnitsOfMeasureUOM
The unit of measure associated with bin values.
cancellationToken: Type: System.ThreadingCancellationToken
A token to control cancellation of the aggregation request.

Type Parameters

TBin: The type of the histogram bins.

Return Value

Type: TaskAFBinnedResultTBin
A result containing the requested histogram or an error if the summaries could not be performed.

Remarks

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.

Examples

// Get the Database
PISystems myPISystems = new PISystems();
PISystem myPISystem = myPISystems.DefaultPISystem;
if (myPISystem == null)
    throw new InvalidOperationException("Default PISystem was not found.");
AFDatabase myDB = myPISystem.Databases[dbName];
if (myDB == null)
    throw new InvalidOperationException("Database was not found.");

// Create a search to find all the event frames created from the 'Event'
// template in the last year.
using (AFEventFrameSearch eventSearch = new AFEventFrameSearch(myDB, "EventFrameSearch", @"Template:'Event' Start:>'t-1y'"))
{
    eventSearch.CacheTimeout = TimeSpan.FromMinutes(10);
    // Generate a histogram by start month
    AFBinnedResult<AFTime> histogram = await eventSearch.HistogramAsync("StartTime",
        new AFTimeSpan(months: 1).GetIntervalTimes(new AFTimeRange("1-1y", "1+1mo")), binUOM: null, cancellationToken: CancellationToken.None);
    foreach (var bin in histogram.BinnedResults)
    {
        Console.WriteLine("Month: {0}, Count: {1}",
            bin.Key, bin.Value[AFSummaryTypes.Count]);
    }
}

' Get the Database
Dim myPISystems As New PISystems()
Dim myPISystem As PISystem = myPISystems.DefaultPISystem
If myPISystem Is Nothing Then
    Throw New InvalidOperationException("Default PISystem was not found.")
End If
Dim myDB As AFDatabase = myPISystem.Databases(dbName)
If myDB Is Nothing Then
    Throw New InvalidOperationException("Database was not found.")
End If

' Create a search to find all the event frames created from the 'Event'
' template in the last year.
Using eventSearch As New AFEventFrameSearch(myDB, "EventFrameSearch", "Template:'Event' Start:>'t-1y'")
    eventSearch.CacheTimeout = TimeSpan.FromMinutes(10)


    ' Generate a histogram by start month
    Dim histogram As AFBinnedResult(Of AFTime) = Await eventSearch.HistogramAsync("StartTime", New AFTimeSpan(months:=1).GetIntervalTimes(New AFTimeRange("1-1y", "1+1mo")), binUOM:=Nothing, cancellationToken:=CancellationToken.None)
    For Each bin As KeyValuePair(Of AFRange(Of AFTime), IReadOnlyDictionary(Of AFSummaryTypes, AFValue)) In histogram.BinnedResults
        Console.WriteLine("Month: {0}, Count: {1}", bin.Key, bin.Value(AFSummaryTypes.Count))
    Next

    Return True
End Using

No code example is currently available or this language may not be supported.

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

AF SDK Reference