IsInstance

Returns true if the argument owlInstance is an actual active property in an active model. It returns false in all other cases, i.e. this could mean the model is already closed, the instance is inactive or removed or the session is closed. It could also mean it represents a handle to another Thing, for example a class, property or model.

Syntax

public const string EngineDLL = @"engine.dll";[DllImport(EngineDLL, EntryPoint = "IsInstance")]
public static extern byte IsInstance(Int64 owlInstance);    

Property owlInstance

Size: 64 bit / 8 byte (value)
The handle to the specific instance in the design tree. The instance handle is static within one open model but is most probably different when the same instance is opened in another model. The instance is always exactly of one unique class.