UOMs Class
- Last UpdatedNov 18, 2025
- 8 minute read
- PI System
- AF SDK 2024 R2
- Developer
A collection of unit-of-measure objects (UOM).

Inheritance Hierarchy
SystemObject
OSIsoft.AFAFCollection
OSIsoft.AFAFCollectionUOM
OSIsoft.AFAFNamedCollectionUOM
OSIsoft.AF.UnitsOfMeasureUOMs
OSIsoft.AFAFCollection
OSIsoft.AFAFCollectionUOM
OSIsoft.AFAFNamedCollectionUOM
OSIsoft.AF.UnitsOfMeasureUOMs
Namespace: OSIsoft.AF.UnitsOfMeasure
Assembly: OSIsoft.AFSDK (in OSIsoft.AFSDK.dll) Version: 3.1.1.1182
Syntax
public sealed class UOMs : AFNamedCollection<UOM>
Public NotInheritable Class UOMs Inherits AFNamedCollection(Of UOM) Dim instance As UOMs
public ref class UOMs sealed : public AFNamedCollection<UOM^>
[<SealedAttribute>] type UOMs = class inherit AFNamedCollection<UOM> end
The UOMs type exposes the following members.
Properties
| Name | Description | |
|---|---|---|
| Class |
This read-only property indicates the class of measurement for this collection of unit of measures.
| |
| Count |
Gets the number of items actually contained in the collection.
(Inherited from AFCollectionT.) | |
| Database |
This read-only property allows access to the UOMDatabase associated with this
object.
| |
| Identity |
This read-only property contains identity of the object.
(Inherited from AFCollection.) | |
| IsDeleted |
This read-only property indicates whether the owner of the collection has been deleted.
(Inherited from AFCollection.) | |
| ItemGuid | Returns the item in the collection associated with the passed in ID. (Inherited from AFCollectionT.) | |
| ItemInt32 | Returns the item located at the passed in index. (Inherited from AFCollectionT.) | |
| ItemString |
Returns the specified object from the collection by name.
(Inherited from AFNamedCollectionT.) | |
| ItemIdentity |
This read-only property specifies the identity of the objects within the collection.
(Inherited from AFCollection.) | |
| PISystem |
This read-only property allows access to the PISystem
associated with this collection.
(Inherited from AFCollection.) |
Methods
| Name | Description | |
|---|---|---|
| Add(T) |
Adds an object to the end of the collection.
(Inherited from AFCollectionT.) | |
| Add(String, String, UOM, Double, Double) |
The Add method creates a new object and adds it to the collection.
| |
| AddFormula |
The AddFormula method creates a new unit-of-measure (UOM) object
and adds it to the collection based on the specified formulas.
| |
| Clear |
Removes all items from the collection.
(Inherited from AFCollectionT.) | |
| Contains(Guid) |
This method determines whether the collection contains a specific item referenced by id.
(Inherited from AFCollectionT.) | |
| Contains(T) |
This method determines whether the collection contains a specific item.
(Inherited from AFCollectionT.) | |
| Contains(String) |
This method determines whether the collection contains a specific item referenced by name.
(Inherited from AFNamedCollectionT.) | |
| CopyTo |
Copies the entire collection to a compatible one-dimensional Array,
starting at the specified index of the target array.
(Inherited from AFCollectionT.) | |
| Equals | Determines whether the specified object is equal to the current object. (Inherited from Object.) | |
| GetEnumerator |
Returns an enumerator that iterates through the collection.
(Inherited from AFCollectionT.) | |
| GetHashCode |
Gets the hash code for this instance of the object which is suitable for use in hashing
algorithms and data structures like a hash table.
(Inherited from AFCollection.) | |
| 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.
(Inherited from AFCollectionT.) | |
| Remove(Guid) |
Removes the item with the specified id from the collection.
(Inherited from AFCollectionT.) | |
| Remove(T) |
Removes the first occurrence of a specific object from the collection.
(Inherited from AFCollectionT.) | |
| Remove(String) |
The Remove method removes the item from the collection by name.
(Inherited from AFNamedCollectionT.) | |
| RemoveAt |
Removes the item at the specified index of the collection.
(Inherited from AFCollectionT.) | |
| Sort |
Sorts the items in the entire collection using the default comparer.
(Inherited from AFCollectionT.) | |
| Sort(IComparerT) |
Sorts the items in the entire collection using the specified comparer.
(Inherited from AFCollectionT.) | |
| Sort(Int32, Int32, IComparerT) |
Sorts the items in a range of items in the collection using the specified comparer.
(Inherited from AFCollectionT.) | |
| ToString |
Returns a String that represents the current object.
(Inherited from AFCollection.) |
Remarks
The global UOMs collection maintained by the Units Of Measure Database represents all the defined units of measure on an UOMDatabase. You add a UOM to the global list of UOMs only by using the Add(String, String, UOM, Double, Double) method of the UOMDatabase.UOMs collection.
Each UOMClass provides a list of UOMs which apply only to that fundamental unit-of-measure dimensions.
Examples
// This example will create several UOMs of the same UOM class // and then demonstrate how to perform conversions between them. // Get the Database PISystems myPISystems = new PISystems(); UOMDatabase myDB = myPISystems.DefaultPISystem.UOMDatabase; // Set the UOM Class UOMClass LengthUOMClass = myDB.UOMClasses.Add("QALength", "QAmeter", "QAm"); // Create UOMs UOM Meter = myDB.UOMs["QAmeter"]; UOM Inch = myDB.UOMs.Add("QAinch", "QAin", Meter, 0.0254, 0); UOM Foot = myDB.UOMs.Add("QAfoot", "QAft", Inch, 12, 0); UOM Yard = myDB.UOMs.Add("QAyard", "QAyd", Inch, 3 * 12, 0); UOM Mile = myDB.UOMs.Add("QAmile", "QAmi", Foot, 5280, 0); // Display Information each UOM foreach (UOM CurUom in myDB.UOMClasses["QALength"].UOMs) { Console.WriteLine("Name of UOM = {0}", CurUom.Name); Console.WriteLine("Abbreviation = {0}", CurUom.Abbreviation); } // Convert 18 Inches to Feet Console.WriteLine("18 Inches converted to Feet = {0}", Foot.Convert(18, Inch)); // Update the Formula for the Yard UOM Yard.Update(Foot, 3.0, 0); // Convert 18 Inches to Yards Console.WriteLine("18 Inches converted to Yards = {0}", Yard.Convert(18, Inch));
' This example will create several UOMs of the same UOM class ' and then demonstrate how to perform conversions between them. ' Get the Database Dim myPISystems As New PISystems Dim myDB As UOMDatabase = myPISystems.DefaultPISystem.UOMDatabase ' Set the UOM Class Dim LengthUOMClass As UOMClass = myDB.UOMClasses.Add("QALength", "QAmeter", "QAm") ' Create UOMs Dim Meter As UOM = myDB.UOMs("QAmeter") Dim Inch As UOM = myDB.UOMs.Add("QAinch", "QAin", Meter, 0.0254, 0) Dim Foot As UOM = myDB.UOMs.Add("QAfoot", "QAft", Inch, 12.0#, 0) Dim Yard As UOM = myDB.UOMs.Add("QAyard", "QAyd", Inch, 3.0# * 12.0#, 0) Dim Mile As UOM = myDB.UOMs.Add("QAmile", "QAmi", Foot, 5280.0#, 0) ' Display Information each UOM Dim CurUOM As UOM For Each CurUOM In myDB.UOMClasses("QALength").UOMs Console.WriteLine("Name of UOM = {0}", CurUOM.Name) Console.WriteLine("Abbreviation = {0}", CurUOM.Abbreviation) Next CurUOM ' Convert 18 Inches to Feet Console.WriteLine("18 Inches converted to Feet = {0}", Foot.Convert(18, Inch)) ' Update the Formula for the Yard UOM Yard.Update(Foot, 3.0#, 0) ' Convert 18 Inches to Yards Console.WriteLine("18 Inches converted to Yards = {0}", Yard.Convert(18, Inch))
No code example is currently available or this language may not be supported.
No code example is currently available or this language may not be supported.