In the TGrid registry I have a BLOB SQL column that I display in TGrid as ImageStyle. Everything works fine, there are no errors.
However, in TGrid I need to change the color of the rows. Selected row – color1, remaining rows – color2. And this is where my problems begin. I couldn’t find a simple way to solve my problem, so I started adding lines of code. first I removed problems with coloring, then problems arose with photos not being visible in the registry. Currently, I have the effect I wanted (there are colors and photos), but after scrolling down the lines, the program crashes with the error “Access violation at address 00F3C2D7 in module ‘Katalog_klockow_21.exe’. Read of address 0000000C.”.

I tried debugging, but I am unable to locate which line the error occurs on. Event
OnDrawColumnCell causes it to run as soon as you hover the cursor over the slider, so I can’t even move it.

I would like to point out that as long as I did not modify the color, the registry worked without errors and the photos were displayed correctly.

I am asking for advice on how I should deal with the seemingly simple color change.

My code:

private
    { Private declarations }
    FSelectedRow: Integer;

procedure TZ.RejestrCellClick(const Column: TColumn; const Row: Integer);
begin
  Rejestr.SelectRow(Row);
  FSelectedRow := Row;
  Rejestr.Repaint;  // Odśwież grid, aby ponownie narysować komórki
end;

procedure TZ.RejestrDrawColumnCell(Sender: TObject; const Canvas: TCanvas;
  const Column: TColumn; const Bounds: TRectF; const Row: Integer;
  const Value: TValue; const State: TGridDrawStates);
begin
    UstawWygladRejestru  (Sender, Canvas, Column, Bounds, Row, Value,State, FSelectedRow);
end;


procedure TZ.UstawWygladRejestru (Sender: TObject; const Canvas: TCanvas;
  const Column: TColumn; const Bounds: TRectF; const Row: Integer;
  const Value: TValue; const State: TGridDrawStates; Wiersz: Integer);
begin

//exit;

var  Bitmap: TBitmap;

begin
  if Row = Wiersz then
    Canvas.Fill.Color := TAlphaColors.Bisque
  else
    Canvas.Fill.Color := TAlphaColors.Beige;

  Canvas.FillRect(Bounds, 0, 0, [], 1);

  if Column is TImageColumn then
    begin

      if Value.IsType<TBitmap> then
      begin
        Bitmap := Value.AsType<TBitmap>;

        Canvas.DrawBitmap(Bitmap, RectF(0, 0, Bounds.Width, Bounds.Height),
                          Bounds, 1, True);

      end;
    end
  else
    begin
      Canvas.Fill.Color := TAlphaColors.Black;
      Canvas.FillText(Bounds, Value.ToString, False, 1, [], TTextAlign.Leading, TTextAlign.Center);
    end;
end;

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So far, I’ve been focusing on finding the simplest solution. The moment I found it, it turned out that I had the “Acces Violaion…” error.