ObjectId Structure

SystemObject
  SystemValueType
    Teigha.DatabaseServicesObjectId

	Name	Description
	ObjectId	Constructs an object ID based on an old integer pointer.

Top

	Name	Description
	Database	Property that represents a database that stores an object associated with this identifier.
	Handle	Property that represents the database handle of the object referenced by this ObjectId object.
	IsEffectivelyErased	Property that indicates whether the object associated with this ObjectId object is erased, or any of its ownership hierarchy is erased.
	IsErased	Property that indicates whether the object associated with this identifier is erased.
	IsNull	Property that indicates whether the identifier is Null.
	IsResident	Property that indicates whether the object associated with this objectId is resident in memory.
	IsValid	Property that indicates whether the object ID is associated with a database that is available. If the Object ID belongs to a database that is no longer available (in other words, is deleted), the value is false.
	NonForwardedHandle	Property that represents the database handle of the object referenced by this ObjectId object.
	Null	Property that represents the Null identifier.
	ObjectClass	Property that represents the RXClass of the object that is associated with the object ID. With this property the result can be safely de-referenced and correctly compared against any class derived from DBObject.
	ObjectLeftOnDisk	For internal use only.
	OldId	Obsolete. Property that represents the identifier's value as a long, which is the old format.
	OldIdPtr	Property that represents the identifier's value as a long, which is the old format.
	OriginalDatabase	If this object ID is in an externally referenced database and the object associated with this object ID has been redirected to the host database, this property returns a pointer to the externall referenced database.

Top

	Name	Description
	Compare	Compares the input identifier with this identifier to check whether they are equal.
	ConvertToRedirectedId	Returns the actual ObjectId object for a database if this ObjectId object has been redirected from another database (for example, an external reference).
	Equals	Checks objects for equality. (Overrides ValueTypeEquals(Object))
	GetHashCode	Retrieves the object hash code. (Overrides ValueTypeGetHashCode)
	GetObject(OpenMode)	Returns the object associated with this ID.
	GetObject(OpenMode, Boolean)	Returns the object associated with this ID.
	GetObject(OpenMode, Boolean, Boolean)	Returns the object associated with this ID.
	GetType	Gets the Type of the current instance. (Inherited from Object)
	Open(OpenMode)	Obsolete. Returns the object associated with this ID.
	Open(OpenMode, Boolean)	Obsolete. Returns the object associated with this ID.
	Open(OpenMode, Boolean, Boolean)	Obsolete. Returns the object associated with this ID.
	ToString	Returns an equivalent string representation of this object. (Overrides ValueTypeToString)
	ToString(IFormatProvider)	Returns an equivalent string representation of this object.

Top

	Name	Description
	Equality(ObjectId, ObjectId)	Equality operator for the ObjectId class.
	GreaterThan(ObjectId, ObjectId)	The 'greater than' operator for the ObjectId class.
	Inequality(ObjectId, ObjectId)	Inequality operator for the ObjectId class.
	LessThan(ObjectId, ObjectId)	The 'less than' operator for the ObjectId class.

Top

Database objects reference other database objects using ObjectId objects. You must explicitly open an object before reading or writing to it, and you should release it when the operation is completed. This functionality provides the support for partial loading of a database, where ObjectId objects exist for all objects in the database, but the actual database objects need not be loaded until they are accessed. It also allows database objects that are not in use to be swapped out of memory, and loaded back in when they are accessed. ObjectId objects are not written out to a DWG/DXF file. If a reference must be preserved to a database object that has been serialized, the object's database handle should be used.

Reference