use \helpref{GetFullPath}{wxfilenamegetfullpath}.
If it is not known wether a string contains a directory name or
a complete file name (such as when interpreting user input) you need to use
the static function \helpref{wxFileName::DirExists}{wxfilenamedirexists}
use \helpref{GetFullPath}{wxfilenamegetfullpath}.
If it is not known wether a string contains a directory name or
a complete file name (such as when interpreting user input) you need to use
the static function \helpref{wxFileName::DirExists}{wxfilenamedirexists}