AF SDK Reference

AFAnnotations Class

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AFAnnotations Class

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Last UpdatedNov 18, 2025
7 minute read

AFAnnotations Class

A list of structured AFAnnotation objects associated with an historical data event.

Inheritance Hierarchy

SystemObject
OSIsoft.AF.DataAFAnnotations

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

Syntax

public sealed class AFAnnotations : IList<AFAnnotation>, 
	ICollection<AFAnnotation>, IEnumerable<AFAnnotation>, IEnumerable, 
	IList, ICollection

Public NotInheritable Class AFAnnotations
	Implements IList(Of AFAnnotation), ICollection(Of AFAnnotation), 
	IEnumerable(Of AFAnnotation), IEnumerable, IList, ICollection

Dim instance As AFAnnotations

public ref class AFAnnotations sealed : IList<AFAnnotation^>, 
	ICollection<AFAnnotation^>, IEnumerable<AFAnnotation^>, IEnumerable, 
	IList, ICollection

[<SealedAttribute>]
type AFAnnotations =  
    class
        interface IList<AFAnnotation>
        interface ICollection<AFAnnotation>
        interface IEnumerable<AFAnnotation>
        interface IEnumerable
        interface IList
        interface ICollection
    end

The AFAnnotations type exposes the following members.

Constructors

	Name	Description
	AFAnnotations	Initializes a new instance of the AFAnnotations class

Properties

	Name	Description
	Count	Gets the number of items actually contained in the collection.
	Item	Gets or sets the item at the specified index.

Methods

	Name	Description
	Add	Create a new AFAnnotation object and adds it to the list.
	Clear	Removes all items from the collection.
	Contains	The Contains method determines if an AFAnnotation exists in the list.
	CopyTo	Copies the entire collection to a compatible one-dimensional Array, starting at the specified index of the target array.
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object.)
	GetEnumerator	Returns an enumerator that iterates through the collection.
	GetHashCode	Serves as the default hash function. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	IndexOf	Searches for the specified object and returns the zero-based index of the first occurrence within the entire collection.
	Insert	Inserts an item into the collection at the specified index.
	Remove	Removes the first occurrence of a specific object from the collection.
	RemoveAt	Removes the item at the specified index of the collection.
	ToString	Returns a string that represents the current object. (Inherited from Object.)

Extension Methods

	Name	Description
	ChunkedByAFAnnotation	This extension method breaks up search results into chunks to make it easier to page through and process IEnumerableT collections in chunks. (Defined by AFSDKExtension.)

Remarks

A list of structured AFAnnotation objects associated with an historical data event. This list can be returned from the AFValue.GetAnnotation method. Because it is a list, there can be more than one structured AFAnnotation per AFValue. This collection of annotations is only used with structured historical data events. Annotations associated with asset data such as AFEventFrame or AFElement are returned as a simple list of AFAnnotation objects and do not use this class.

Important
This list only supports PIPoint annotations.

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

Examples

// This example demonstrates how to create an attribute for an
// element and retrieve and set annotations on values.

// Get the Database
PISystems myPISystems = new PISystems();
PISystem myPISystem = myPISystems.DefaultPISystem;
AFDatabase myDB = myPISystem.Databases.DefaultDatabase;

// Create an Element
AFElement myElement = myDB.Elements.Add("MyElement");

// Create an Attribute
AFAttribute myAttribute = myElement.Attributes.Add("MyAttribute");
myAttribute.DefaultUOM = myPISystem.UOMDatabase.UOMs["kelvin"];
myAttribute.DataReferencePlugIn = AFDataReference.GetPIPointDataReference(myPISystem);
myAttribute.ConfigString = @"\\%Server%\sinusoid;ReadOnly=False";

// Create New Simple Annotation
AFValue myValue1 = new AFValue(155.432, AFTime.Now);
myValue1.SetAnnotation("New Event with Simple Annotation");
myAttribute.Data.UpdateValue(myValue1, AFUpdateOption.InsertNoCompression);

// Update an Existing Annotation
myValue1.SetAnnotation(100);
myAttribute.Data.UpdateValue(myValue1, AFUpdateOption.Replace);

// Create an AFFile to be used as an Annotation value
string path = System.IO.Path.Combine(System.IO.Path.GetTempPath(), "TestFile.txt");
using (System.IO.File.Create(path)) { }
AFFile myFile = new AFFile();
myFile.Upload(path);

// Create New Structured Annotation
AFAnnotations myAnnotations = new AFAnnotations();
AFValue myValue2 = new AFValue(255.543);
AFAnnotation myAnnotation = myAnnotations.Add("Annotation#1", 400.456);
myAnnotation.Description = "1st Annotation is a Double.";
myAnnotation = myAnnotations.Add("Annotation#2", "My Annotation Value");
myAnnotation.Description = "2nd Annotation is a String.";
myAnnotation = myAnnotations.Add("Annotation#3", myFile);
myAnnotation.Description = "3rd Annotation is an AFFile.";
myValue2.SetAnnotation(myAnnotations);
myAttribute.Data.UpdateValue(myValue2, AFUpdateOption.InsertNoCompression);

// Read Annotations
object theAnnotation = myValue1.GetAnnotation();
DisplayAnnotation(myValue1, theAnnotation);

theAnnotation = myValue2.GetAnnotation();
DisplayAnnotation(myValue2, theAnnotation);

AFValue myValue = myAttribute.GetValue();
theAnnotation = myValue.GetAnnotation();
DisplayAnnotation(myValue, theAnnotation);

' This example demonstrates how to create an attribute for an
' element and retrieve and set annotations on values.

' Get the Database
Dim myPISystems As New PISystems
Dim myPISystem As PISystem = myPISystems.DefaultPISystem
Dim myDB As AFDatabase = myPISystem.Databases.DefaultDatabase

' Create An Element
Dim myElement As AFElement = myDB.Elements.Add("MyElement")

' Create an Attribute
Dim myAttribute As AFAttribute = myElement.Attributes.Add("MyAttribute")
myAttribute.DefaultUOM = myPISystem.UOMDatabase.UOMs("Kelvin")
myAttribute.DataReferencePlugIn = AFDataReference.GetPIPointDataReference(myPISystem)
myAttribute.ConfigString = "\\%Server%\sinusoid;ReadOnly=False"

' Create New Simple Annotation
Dim myValue1 As AFValue = New AFValue(155.432, AFTime.Now)
myValue1.SetAnnotation("New Event with Simple Annotation")
myAttribute.Data.UpdateValue(myValue1, AFUpdateOption.InsertNoCompression)

' Update an Existing Annotation
myValue1.SetAnnotation(100)
myAttribute.Data.UpdateValue(myValue1, AFUpdateOption.Replace)

' Create an AFFile to be used as an Annotation value
Dim path As String = System.IO.Path.Combine(System.IO.Path.GetTempPath(), "TestFile.txt")
Dim fs As FileStream = System.IO.File.Create(path)
fs.Close()
Dim myFile As AFFile = New AFFile
myFile.Upload(path)

' Create New Structured Annotation
Dim myAnnotations As AFAnnotations = New AFAnnotations
Dim myValue2 As AFValue = New AFValue(255.543)
Dim myAnnotation As AFAnnotation = myAnnotations.Add("Annotation#1", 400.456)
myAnnotation.Description = "1st Annotation is a Double."
myAnnotation = myAnnotations.Add("Annotation#2", "My Annotation Value")
myAnnotation.Description = "2nd Annotation is a String."
myAnnotation = myAnnotations.Add("Annotation#3", myFile)
myAnnotation.Description = "3rd Annotation is an AFFile."
myValue2.SetAnnotation(myAnnotations)
myAttribute.Data.UpdateValue(myValue2, AFUpdateOption.InsertNoCompression)

' Read Annotations
Dim theAnnotation As Object = myValue1.GetAnnotation
DisplayAnnotation(myValue1, theAnnotation)

theAnnotation = myValue2.GetAnnotation
DisplayAnnotation(myValue2, theAnnotation)

Dim myValue As AFValue = myAttribute.GetValue
theAnnotation = myValue.GetAnnotation
DisplayAnnotation(myValue, theAnnotation)

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

/// <summary>
/// Display information about the annotated value.
/// </summary>
/// <param name="theValue">
/// The AFValue associated with the specified annotation value.
/// </param>
/// <param name="theAnnotation">
/// The annotation value associated with the specified AFValue.
/// </param>
static private void DisplayAnnotation(AFValue theValue, object theAnnotation)
{
    AFAnnotations theAnnotations = theAnnotation as AFAnnotations;
    if (theAnnotations == null)
    {
        Console.WriteLine("Simple Annotation for Value '{0}' = '{1}'", theValue, theAnnotation);
    }
    else
    {
        Console.WriteLine("Structured Annotation for Value '{0}':", theValue);
        foreach (AFAnnotation item in theAnnotations)
        {
            Console.WriteLine("  Value = '{0}', Description = '{1}', Creator = '{2}'",
                item.Value, item.Description, item.Creator);
        }
    }
}

''' <summary>
''' Display information about the annotated value.
''' </summary>
''' <param name="theValue">
''' The AFValue associated with the specified annotation value.
''' </param>
''' <param name="theAnnotation">
''' The annotation value associated with the specified AFValue.
''' </param>
Private Shared Sub DisplayAnnotation(ByVal theValue As AFValue, ByVal theAnnotation As Object)
    Dim theAnnotations As AFAnnotations = TryCast(theAnnotation, AFAnnotations)
    If (theAnnotations Is Nothing) Then
        Console.WriteLine("Simple Annotation for Value '{0}' = '{1}'", theValue, theAnnotation)
    Else
        Console.WriteLine("Structured Annotation for Value '{0}':", theValue)
        For Each item As AFAnnotation In theAnnotations
            Console.WriteLine("  Value = '{0}', Description = '{1}', Creator = '{2}'", item.Value, item.Description, item.Creator)
        Next
    End If
End Sub

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

AF SDK Reference