AF SDK Reference

PIPoint.UnloadAllAttributes Method

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PIPoint.UnloadAllAttributes Method

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Last UpdatedJan 12, 2026
3 minute read

Unload all PIPoint attributes from the cache except for the specified names.

Namespace: OSIsoft.AF.PI
Assembly: OSIsoft.AFSDK (in OSIsoft.AFSDK.dll) Version: 3.2.0.7

Syntax

public void UnloadAllAttributes(
	params string[] exceptNames
)

Public Sub UnloadAllAttributes ( 
	ParamArray exceptNames As String()
)

Dim instance As PIPoint
Dim exceptNames As String()

instance.UnloadAllAttributes(exceptNames)

public:
void UnloadAllAttributes(
	... array<String^>^ exceptNames
)

member UnloadAllAttributes : 
        exceptNames : string[] -> unit

Parameters

exceptNames: Type: SystemString
The list of attribute names not to unload. If or an empty list, then all attributes will be unloaded. The PICommonPointAttributes class contains some of the common PIPoint attribute names.

Remarks

All PIPoint attribute are unloaded from the client's cache except for the specified list of attributes not to unload. 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);
    }
}

AF SDK Reference