FileFilter.this

Creates a new gtk.FileFilter with no rules added to it. Such a filter doesn’t accept any files, so is not particularly useful until you add rules with FileFilter.addMimeType, FileFilter.addPattern, or FileFilter.addCustom. To create a filter that accepts any file, use:

GtkFileFilter *filter = gtk_file_filter_new ();
gtk_file_filter_add_pattern (filter, "*");