Files - How to access ADD LINK button from Code Level

Hi, Add Link button creates link between File and some Entity. To create this link from code you need to insert into NoteDoc NoteID of an Entity and FileID of a File. You can use code of Add Link button: 
 

    protected IEnumerable addLink(PXAdapter a)
    {
        try
        {
            PXFilter<FileDialog> fileDialog = FileDialog;
            if (fileDialog != null && (fileDialog.Current?.Entity).HasValue && Files.Current != null)
            {
                PXDatabase.Insert<NoteDoc>(new PXDataFieldAssign[2]
                {
                    new PXDataFieldAssign("NoteID", PXDbType.UniqueIdentifier, FileDialog?.Current?.Entity),
                    new PXDataFieldAssign("FileID", PXDbType.UniqueIdentifier, Files.Current.FileID)
                });
            }

            return a.Get();
        }
        catch (PXDatabaseException ex)
        {
            if (ex.ErrorCode != PXDbExceptions.PrimaryKeyConstraintViolation)
            {
                throw ex;
            }

            throw new Exception("Can't insert link more than once", ex);
        }
    }