AF SDK Reference

PIPoint.UnloadAttributes Method

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PIPoint.UnloadAttributes Method

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Last UpdatedNov 18, 2025
5 minute read

Unload PIPoint attributes from the cache.

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

Syntax

public void UnloadAttributes(
	params string[] names
)

Public Sub UnloadAttributes ( 
	ParamArray names As String()
)

Dim instance As PIPoint
Dim names As String()

instance.UnloadAttributes(names)

public:
void UnloadAttributes(
	... array<String^>^ names
)

member UnloadAttributes : 
        names : string[] -> unit

Parameters

names: Type: SystemString
The list of PIPoint attribute names to be unloaded loaded. The PICommonPointAttributes class contains some of the common PIPoint attribute names.

Remarks

The PIPoint attributes for the specified list of names are unloaded from the client's cache. This method is used to free memory when PIPoint attributes are no longer needed, but the PIPoint is still being used. Note that ID, Name, PointType, Step, and Future attributes are not unloaded from the cache.

Examples

// This example demonstrates how to create an attribute for an
// element and retrieve and set PIPoint attributes.

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

// Create an Element Template
AFElementTemplate myElemTemplate = myDB.ElementTemplates.Add("MyElementTemplate");
AFAttributeTemplate myAttrTemplate = myElemTemplate.AttributeTemplates.Add("Attr#1");
myAttrTemplate.DataReferencePlugIn = AFDataReference.GetPIPointDataReference(myPISystem);
myAttrTemplate.ConfigString = @"\\%Server%\%Element%;pointtype=Float64";

// Create an Element from the Element Template
AFElement myElement = myDB.Elements.Add("MyElement", myElemTemplate);

// Create the PIPoint for the Attribute
AFAttribute myAttribute = myElement.Attributes["Attr#1"];
myAttribute.DataReference.CreateConfig();

// Find all PIPoint Attributes and Display their values
object drAttrValue;
myAttribute.PIPoint.LoadAttributes();
IEnumerable<string> list = myAttribute.PIPoint.FindAttributeNames(null);
Console.WriteLine("Found PIPoint Attributes: nameFilter='<null>'");
foreach (string item in list)
{
    drAttrValue = myAttribute.PIPoint.GetAttribute(item);
    Console.WriteLine("  {0} = '{1}'", item, drAttrValue);
}
Console.WriteLine();

// Find PIPoint Attributes matching 'Ex*' and display their values
list = myAttribute.PIPoint.FindAttributeNames("Ex*");
Console.WriteLine("Found PIPoint Attributes: nameFilter='Ex*'");
int cnt = 0;
foreach (string item in list)
{
    cnt++;
    drAttrValue = myAttribute.PIPoint.GetAttribute(item);
    Console.WriteLine("  {0} = '{1}'", item, drAttrValue);
}
Console.WriteLine();

// Unload all PIPoint Attributes
myAttribute.PIPoint.UnloadAllAttributes();

// Load specific PIPoint Attributes and display their values
myAttribute.PIPoint.LoadAttributes(PICommonPointAttributes.PointType,
    PICommonPointAttributes.PointID,
    PICommonPointAttributes.Descriptor,
    PICommonPointAttributes.ExtendedDescriptor,
    PICommonPointAttributes.CreationDate);
drAttrValue = myAttribute.PIPoint.GetAttribute(PICommonPointAttributes.PointType);
Console.WriteLine("PIPoint Attribute '{0}' = '{1}'.", PICommonPointAttributes.PointType, drAttrValue);
drAttrValue = myAttribute.PIPoint.GetAttribute(PICommonPointAttributes.PointID);
Console.WriteLine("PIPoint Attribute '{0}' = '{1}'.", PICommonPointAttributes.PointID, drAttrValue);
drAttrValue = myAttribute.PIPoint.GetAttribute(PICommonPointAttributes.Descriptor);
Console.WriteLine("PIPoint Attribute '{0}' = '{1}'.", PICommonPointAttributes.Descriptor, drAttrValue);
drAttrValue = myAttribute.PIPoint.GetAttribute(PICommonPointAttributes.ExtendedDescriptor);
Console.WriteLine("PIPoint Attribute '{0}' = '{1}'.", PICommonPointAttributes.ExtendedDescriptor, drAttrValue);
drAttrValue = myAttribute.PIPoint.GetAttribute(PICommonPointAttributes.CreationDate);
Console.WriteLine("PIPoint Attribute '{0}' = '{1}'.", PICommonPointAttributes.CreationDate, drAttrValue);
Console.WriteLine();

// Set PIPoint Attribute value
string newAttrValue = "New Value: " + DateTime.Now.ToShortTimeString();
myAttribute.PIPoint.SetAttribute(PICommonPointAttributes.Descriptor, newAttrValue);
myAttribute.PIPoint.SetAttribute(PICommonPointAttributes.ExtendedDescriptor, newAttrValue);
AFErrors<string> errors = myAttribute.PIPoint.SaveAttributes(PICommonPointAttributes.Descriptor,
    PICommonPointAttributes.ExtendedDescriptor);
if (errors != null && errors.HasErrors)
{
    Console.WriteLine("Errors calling PIPoint.SaveAttributes:");
    foreach (var item in errors.Errors)
    {
        Console.WriteLine("  {0}: {1}", item.Key, item.Value);
    }
}

' This example demonstrates how to create an attribute for an
' element and retrieve and set PIPoint attributes.

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

' Create an Element Template
Dim myElemTemplate As AFElementTemplate = myDB.ElementTemplates.Add("MyElementTemplate")
Dim myAttrTemplate As AFAttributeTemplate = myElemTemplate.AttributeTemplates.Add("Attr#1")
myAttrTemplate.DataReferencePlugIn = AFDataReference.GetPIPointDataReference(myPISystem)
myAttrTemplate.ConfigString = "\\%Server%\%Element%;pointtype=Float64"

' Create an Element from the Element Template
Dim myElement As AFElement = myDB.Elements.Add("MyElement", myElemTemplate)

' Create the PIPoint for the Attribute
Dim myAttribute As AFAttribute = myElement.Attributes("Attr#1")
myAttribute.DataReference.CreateConfig()

' Find all PIPoint Attributes and Display their values
Dim drAttrValue As Object
myAttribute.PIPoint.LoadAttributes()
Dim list As IEnumerable(Of String) = myAttribute.PIPoint.FindAttributeNames(Nothing)
Console.WriteLine("Found PIPoint Attributes: nameFilter='<null>'")
For Each item As String In list
    drAttrValue = myAttribute.PIPoint.GetAttribute(item)
    Console.WriteLine("  {0} = '{1}'", item, drAttrValue)
Next
Console.WriteLine()

' Find PIPoint Attributes matching 'Ex*' and display their values
list = myAttribute.PIPoint.FindAttributeNames("Ex*")
Console.WriteLine("Found PIPoint Attributes: nameFilter='Ex*'")
Dim cnt As Integer = 0
For Each item As String In list
    cnt = (cnt + 1)
    drAttrValue = myAttribute.PIPoint.GetAttribute(item)
    Console.WriteLine("  {0} = '{1}'", item, drAttrValue)
Next
Console.WriteLine()

' Unload all PIPoint Attributes
myAttribute.PIPoint.UnloadAllAttributes()

' Load specific PIPoint Attributes and display their values
myAttribute.PIPoint.LoadAttributes(PICommonPointAttributes.PointType,
                                   PICommonPointAttributes.PointID,
                                   PICommonPointAttributes.Descriptor,
                                   PICommonPointAttributes.ExtendedDescriptor,
                                   PICommonPointAttributes.CreationDate)
drAttrValue = myAttribute.PIPoint.GetAttribute(PICommonPointAttributes.PointType)
Console.WriteLine("PIPoint Attribute '{0}' = '{1}'.", PICommonPointAttributes.PointType, drAttrValue)
drAttrValue = myAttribute.PIPoint.GetAttribute(PICommonPointAttributes.PointID)
Console.WriteLine("PIPoint Attribute '{0}' = '{1}'.", PICommonPointAttributes.PointID, drAttrValue)
drAttrValue = myAttribute.PIPoint.GetAttribute(PICommonPointAttributes.Descriptor)
Console.WriteLine("PIPoint Attribute '{0}' = '{1}'.", PICommonPointAttributes.Descriptor, drAttrValue)
drAttrValue = myAttribute.PIPoint.GetAttribute(PICommonPointAttributes.ExtendedDescriptor)
Console.WriteLine("PIPoint Attribute '{0}' = '{1}'.", PICommonPointAttributes.ExtendedDescriptor, drAttrValue)
drAttrValue = myAttribute.PIPoint.GetAttribute(PICommonPointAttributes.CreationDate)
Console.WriteLine("PIPoint Attribute '{0}' = '{1}'.", PICommonPointAttributes.CreationDate, drAttrValue)
Console.WriteLine()

' Set PIPoint Attribute value
Dim newAttrValue As String = ("New Value: " + DateTime.Now.ToShortTimeString)
myAttribute.PIPoint.SetAttribute(PICommonPointAttributes.Descriptor, newAttrValue)
myAttribute.PIPoint.SetAttribute(PICommonPointAttributes.ExtendedDescriptor, newAttrValue)
Dim errors As AFErrors(Of String) = myAttribute.PIPoint.SaveAttributes(PICommonPointAttributes.Descriptor,
                                                                       PICommonPointAttributes.ExtendedDescriptor)
If errors IsNot Nothing AndAlso errors.HasErrors Then
    Console.WriteLine("Errors calling PIPoint.SaveAttributes:")
    For Each item As KeyValuePair(Of String, Exception) In errors.Errors
        Console.WriteLine("  {0}: {1}", item.Key, item.Value)
    Next
End If

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

AF SDK Reference