Martin how can use the property TextBetweenPoints to exchange lines. I tried but not work me.

I have this code:
tempStr := ASynEdit.LineText;
ASynEdit.TextBetweenPoints[Point(1, ASynEdit.CaretY), Point(1, ASynEdit.CaretY)]:= ASynEdit.Lines.Strings[ASynEdit.CaretY - 2] +LineEnding;
ASynEdit.TextBetweenPoints[Point(1, ASynEdit.CaretY-1), Point(1, ASynEdit.CaretY-1)]:=tempStr+LineEnding;

previously used this code:

 procedure MoveLineUp(Sender: TObject);
 begin
  if CustSynEdit.CaretY -1 >= 1 then
   begin
    CustSynEdit.Lines.Exchange(CustSynEdit.CaretY -1 ,CustSynEdit.CaretY-2);
    CustSynEdit.CaretY:=CustSynEdit.CaretY-1;
   end;
 end;
 procedure MoveLineDown(Sender: TObject);
 begin
  if ( CustSynEdit.CaretY + 1 <= CustSynEdit.Lines.Count) then
   begin
    CustSynEdit.Lines.Exchange(CustSynEdit.CaretY-1,CustSynEdit.CaretY);
    CustSynEdit.CaretY:=CustSynEdit.CaretY+1;
   end;
 end;

which has the same problem as you pointed out to me.

thanks.

ASynEdit.TextBetweenPoints[Point(1, ASynEdit.CaretY), Point(1, ASynEdit.CaretY)]

Inserts the new text at the begin of the line (x=1). but start and stop of the old text are equal, so nothing is replaced.

ASynEdit.TextBetweenPoints

is lixe
- set selection (or no selection
- delete selection
- insert new
- restore old selection

selecting a full line:

ASynEdit.TextBetweenPoints[Point(1, ASynEdit.CaretY), Point(1, ASynEdit.CaretY + 1)]

additionally ASynEdit.TextBetweenPointsEx can adjust the caret pos

y := ASynEdit.CaretY;
tempStr := ASynEdit.LineText;
ASynEdit.TextBetweenPoints[Point(1, ASynEdit.CaretY), Point(1, ASynEdit.CaretY + 1)]:= ASynEdit.Lines.Strings[ASynEdit.CaretY - 2] +LineEnding;
ASynEdit.TextBetweenPoints[Point(1, ASynEdit.CaretY-1), Point(1, ASynEdit.CaretY)]:=tempStr+LineEnding;