PIPoint.UnloadAttributes Method
- Last UpdatedJan 12, 2026
- 3 minute read
- PI System
- AF SDK 3.2.0
- Developer
Unload PIPoint attributes from the cache.
Namespace: OSIsoft.AF.PI
Assembly: OSIsoft.AFSDK (in OSIsoft.AFSDK.dll) Version: 3.2.0.7
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); } }