Gets the hash code of this document instance.
Assembly: RevitAPI (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0)
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.