Element Class

The smallest individually identifiable building block for modeling the real world in an iModel. Each element represents an Entity in the real world. Sets of Elements (contained in Models) are used to model other Elements that represent larger scale real world entities. Using this recursive modeling strategy, Elements can represent entities at any scale. Elements can represent physical things or abstract concepts or simply be information records.

Every Element has a 64-bit id (inherited from Entity) that uniquely identifies it within an iModel. Every Element also has a code that identifies its meaning in the real world. Additionally, Elements may have a federationGuid to hold a GUID, if the element was assigned that GUID by some other federated database. The iModel database enforces uniqueness of id, code, and federationGuid.

The Element class provides static methods like onInsert, onUpdated, onCloned, and onChildAdded that enable it to customize persistence operations. For example, the base implementations of onInsert, onUpdate, and onDelete validate that the appropriate locks, codes, and channel permissions are obtained before a change to the element is written to the iModel. A subclass of Element that overrides any of these methods must call the super method as well. An application that supplies its own Element subclasses should register them at startup via registerModule or register.

See:

• Element Fundamentals
• Working with schemas and elements in TypeScript
• Creating elements

Extends

• Entity

Extended by

• GeometricElement
• InformationContentElement
• RoleElement

Methods

Name	Description
constructor(props: ElementProps, iModel: IModelDb): Element Protected
collectPredecessorIds(predecessorIds: EntityReferenceSet): void Protected	Collect the Ids of this element's references at this level of the class hierarchy.	Deprecated
collectReferenceIds(referenceIds: EntityReferenceSet): void Protected	Collect the Ids of this entity's references at this level of the class hierarchy.
delete(): void	Delete this Element from the iModel.
getClassMetaData(): undefined | EntityMetaData	Get the class metadata for this element.
getDisplayLabel(): string	Get a display label for this Element.
getJsonProperty(nameSpace: string): any	Get a JSON property of this element, by namespace
getPredecessorIds(): Id64Set	Get the Ids of this element's references.	Deprecated
getToolTipMessage(): string[]	Get a list of HTML strings that describe this Element for the tooltip.
getUserProperties(namespace: string): any	Get a set of JSON user properties by namespace
insert(): string	Insert this Element into the iModel.
removeUserProperties(nameSpace: string): void	Remove a set of JSON user properties, specified by namespace, from this Element
setJsonProperty(nameSpace: string, value: any): void
setUserProperties(nameSpace: string, value: any): void	Change a set of user JSON properties of this Element by namespace.
toJSON(): ElementProps	Obtain the JSON representation of this Entity.
update(): void	Update this Element in the iModel.
onAllInputsHandled(_id: string, _iModel: IModelDb): void Protected Static	Called on an element in a graph after all of its inputs have been processed and before its outputs are processed.
onBeforeOutputsHandled(_id: string, _iModel: IModelDb): void Protected Static	Called when a root element in a subgraph is changed and before its outputs are processed.
onChildAdd(_arg: OnChildElementPropsArg): void Protected Static	Called when an existing element is about to be updated so that an instance of this class will become its new parent.
onChildAdded(_arg: OnChildElementIdArg): void Protected Static	Called after an existing element has been updated so that an instance of this class is its new parent.
onChildDelete(_arg: OnChildElementIdArg): void Protected Static	Called when an element with an instance of this class as its parent is about to be deleted.
onChildDeleted(_arg: OnChildElementIdArg): void Protected Static	Called after an element with an instance of this class as its parent was successfully deleted.
onChildDrop(_arg: OnChildElementIdArg): void Protected Static	Called when an element with an instance of this class as its parent is about to be updated change to a different parent.
onChildDropped(_arg: OnChildElementIdArg): void Protected Static	Called after an element with an instance of this class as its previous parent was updated to have a new parent.
onChildInsert(_arg: OnChildElementPropsArg): void Protected Static	Called when a new element with an instance of this class as its parent is about to be inserted.
onChildInserted(_arg: OnChildElementIdArg): void Protected Static	Called after a new element with an instance of this class as its parent was inserted.
onChildUpdate(_arg: OnChildElementPropsArg): void Protected Static	Called when an element with an instance of this class as its parent is about to be updated.
onChildUpdated(_arg: OnChildElementIdArg): void Protected Static	Called after an element with an instance of this the class as its parent was updated.
onCloned(_context: IModelElementCloneContext, _sourceProps: ElementProps, _targetProps: ElementProps): void Protected Static	Called during the iModel transformation process after an Element from the source iModel was cloned for the target iModel.
onDelete(arg: OnElementIdArg): void Protected Static	Called before an Element is deleted.
onDeleted(_arg: OnElementIdArg): void Protected Static	Called after an Element was deleted.
onInsert(arg: OnElementPropsArg): void Protected Static	Called before a new Element is inserted.
onInserted(arg: OnElementIdArg): void Protected Static	Called after a new Element was inserted.
onSubModelDelete(_arg: OnSubModelIdArg): void Protected Static	Called when a sub-model of an instance of this class is being deleted.
onSubModelDeleted(_arg: OnSubModelIdArg): void Protected Static	Called after a sub-model of an instance of this class was deleted.
onSubModelInsert(_arg: OnSubModelPropsArg): void Protected Static	Called when an instance of this class is being sub-modeled by a new Model.
onSubModelInserted(_arg: OnSubModelIdArg): void Protected Static	Called after an instance of this class was sub-modeled by a new Model.
onUpdate(arg: OnElementPropsArg): void Protected Static	Called before an Element is updated.
onUpdated(_arg: OnElementIdArg): void Protected Static	Called after an Element was updated.

Inherited methods

Name	Inherited from	Description
forEachProperty(func: PropertyCallback, includeCustom: booleantrue): void Inherited	Entity	Call a function for each property of this Entity.
getReferenceIds(): EntityReferenceSet Inherited	Entity	Get the set of this entity's entity references, EntityReferenceSet.
is(otherClass: ): boolean Static Inherited	Entity	return whether this Entity class is a subclass of another Entity class

Properties

Name	Type	Description
className Accessor Static ReadOnly	string	The name of the BIS class associated with this class.
code	Code	The Code for this element
federationGuid	string | undefined	A FederationGuid assigned to this element by some other federated database
jsonProperties Readonly	{ T }	Optional json properties of this element.
model Readonly	string	The ModelId of the Model containing this element
parent	RelatedElement | undefined	The parent element, if present, of this element.
requiredReferenceKeys Static Readonly	ReadonlyArray	A required reference is an element that had to be inserted before this element could have been inserted.
userLabel	string | undefined	A user-assigned label for this element.

Inherited properties

Name	Type	Inherited from	Description
classFullName Accessor Inherited ReadOnly	string	Entity	Get the full BIS class name of this Entity in the form "schema:class".
classFullName Accessor Static Inherited ReadOnly	string	Entity	Get the full BIS class name of this Entity in the form "schema:class"
className Accessor Inherited ReadOnly	string	Entity	The name of the BIS class associated with this class.
id Inherited	string	Entity	The Id of this Entity.
iModel Inherited	IModelDb	Entity	The IModelDb that contains this Entity
isInstanceOfEntity Readonly Inherited	"true"	Entity	An immutable property used to discriminate between Entity and EntityProps, used to inform the TypeScript compiler that these two types
schema Static Inherited		Entity	The Schema that defines this class.
schemaName Accessor Inherited ReadOnly	string	Entity	The name of the BIS Schema that defines this class

Defined in

• core/backend/src/Element.ts Line 119