Adds the currently active document to this project item if it is a valid child. Otherwise, the document is added to the Mapping Folder of the project's root.
AddActiveFile() -> ProjectItem
The object is no longer valid.
The file name is empty. Invalid address for the return parameter was specified.
No active document is available.
Active documents needs to be given a path name before it can be added to the project.
Mapping could not be assigned to project. The file does not exist or is not a MapForce mapping. Maybe the file is already assigned to the target folder.