The document's title. 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0) 
Syntax
Remarks
 A title is usually derived from the document's filename. Note that the title will be empty if a document is detached. See  IsDetached  .