The fully qualified path of the document's disk file.
Assembly: RevitAPI (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0)
This string is empty if the project has not been saved or does not have a disk file associated with it yet. Note that the pathname will be empty if a document is detached. See IsDetached .
string docPathName = document.PathName;
Dim docPathName As String = document.PathName