高亮 TRichEdit 当前行

var

  gStart, gLength, gCol: Integer;

procedure SetRichEdit(aRichEdit: TRichEdit);

var

  fRow, fCol: Integer;

  fStart, fLength, tStart: Integer;

begin

  fRow := aRichEdit.CaretPos.X;

  fCol := aRichEdit.CaretPos.Y;

  if gCol = fCol then Exit;

  if aRichEdit.SelLength >  then Exit;

  tStart := aRichEdit.SelStart;

  fStart := tStart - fRow;

  fLength := aRichEdit.Lines[fCol].Length;

  aRichEdit.Lines.BeginUpdate;

  if fLength >  then

  begin

    aRichEdit.SelStart := fStart;

    aRichEdit.SelLength := fLength;

    aRichEdit.SelAttributes.Color := clRed;

  end;

  if gLength >  then

  begin

    aRichEdit.SelStart := gStart;

    aRichEdit.SelLength := gLength;

//    aRichEdit.SelectAll;

    aRichEdit.SelAttributes.Color := clBlack;

  end;

  aRichEdit.SelStart := tStart;

  aRichEdit.SelLength := ;

  aRichEdit.Lines.EndUpdate;

  gStart := fStart;

  gLength := fLength;

  gCol := fCol;

end;

procedure TForm1.RichEdit1Click(Sender: TObject);

begin

  SetRichEdit(TRichEdit(Sender));

end;

procedure TForm1.RichEdit1KeyUp(Sender: TObject; var Key: Word; Shift: TShiftState);

begin

  if Key in [..] then SetRichEdit(TRichEdit(Sender));

end;