Setting the SOLine notes via code is not working

Hi Everyone,
I’m creating a processing form to process SOLines based on some functionality, a part of the code is to set the Line note for each SOLine. i tried joining the SOLine to Note table on NoteID. and tried a second way to update the Note table on the database:

 

var note = PXSelect<Note,
                         Where<Note.noteID, Equal<Required<Note.noteID>>>>
                         .Select(graph, soLine.NoteID)
                         .FirstOrDefault()?.GetItem<Note>();

var lineNoteText = "...........";

note.NoteText = lineNoteText;

a “Null Object reference” raised for the note variable. so i thought to use the seconde one:

 

PXDatabase.Update<Note>(
        new PXDataFieldAssign<Note.noteText>(lineNoteText),
        new PXDataFieldRestrict<Note.noteID>(soLine.NoteID)
    );

none of them worked…

any thoughts?