FileTypeSet.All
From Xojo Documentation
Read-Only Property (As String )
Contains all of the file types in the File Type Set.
This property is only available for File Types that are created in the File Types Set Editor.
Examples
Var allTypes As String
allTypes = FileTypes1.All // FileType1 is a File Type Set created in the File Types Set Editor
allTypes = FileTypes1.All // FileType1 is a File Type Set created in the File Types Set Editor