public override int GetHashCode()

Public Overrides Function GetHashCode As Integer

public:
virtual int GetHashCode() override

The hash code is the same for document instances that represent the same document currently opened in the Revit session. The hash code is generated when a Revit file is opened or created in session. If the same Revit file is opened later (in the same session or a different session) the hash code will not be the same.