ElementId Class

The ElementId object is used as a unique identification for an element within a single project.

Inheritance Hierarchy

System.Object
Autodesk.Revit.DB.ElementId

Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 26.4.0.0 (26.4.0.0)

Syntax

C#

public class ElementId : IComparable

The ElementId type exposes the following members.

Constructors

	Name	Description
	ElementId(BuiltInCategory)	Create an ElementId handle with the given BuiltInCategory id.
	ElementId(BuiltInParameter)	Create an ElementId handle with the given BuiltInParameter id.
	ElementId(Int64)	Create an ElementId handle with the given 64-bit integer id.

Properties

	Name	Description
	InvalidElementId	Get the invalid ElementId whose value is -1.
	Value	Provides the value of the element id as a 64-bit integer.

Methods

	Name	Description
	Compare	Compares two element ids.
	CompareTo	Compares two element ids. Implementation of System.IComparable interface
	Equals	Determines whether the specified Object is equal to the current Object. (Overrides Object.Equals(Object))
	GetHashCode	Gets the value of the id as hash code (Overrides Object.GetHashCode())
	GetType	Gets the Type of the current instance. (Inherited from Object)
	Parse	Parse the string representation of the id into a corresponding ElementId.
	ToString	Gets a String representation of the value of the id. (Overrides Object.ToString())
	TryParse	Parse the string representation of the id into a corresponding ElementId.

Operators

	Name	Description
	Equality(ElementId, ElementId)	Determines whether these two ElementIds are the same.
	GreaterThan(ElementId, ElementId)	Determines whether one element id is greater than another element id.
	GreaterThanOrEqual(ElementId, ElementId)	Determines whether one element id is not less than another element id.
	Inequality(ElementId, ElementId)	Determines whether these two ElementIds are different.
	LessThan(ElementId, ElementId)	Determines whether this element id is less than another element id.
	LessThanOrEqual(ElementId, ElementId)	Determines whether one element id is not greater than another element id.

Remarks

The Value within the ElementId is only unique with a single project. It is not unique across several projects. The Id can be used to retrieve a specific element from the database when needed. However ids are subject to change during an Autodesk Revit session and as such should not be retained and used across repeated calls to external commands. If a manner is needed to uniquely identify an element beyond this limitation then a shared parameter should be added to the element containing a unique identifier managed by the external application.