The URI to the file.
For the default plaform, attempting to set this property to a
value which is not a valid URI will result in an exception being
thrown. To convert a standard Windows path to a URI use (new
For some values of the Platform property (e.g. Mac, DOS, Unix)
raw file paths can be used. However these are obsolete and while
you may see PDFs which contain them, you would be inadvised to
generate new documents containing these structures.