The base directory that contains workbook. If the value is not a null reference (Nothing in Visual Basic) (Nothing), Name is the file name of workbook. If the value is empty, the path is the root directory.
Caution: System.IO.Path.Combine(System.String,System.String) has different strategy for System.String.Empty and a null reference (Nothing in Visual Basic) (Nothing). Check this value with System.String.IsNullOrEmpty(System.String) (or use = Nothing in Visual Basic) before passing it to System.IO.Path.Combine(System.String,System.String).
