http://docwiki.embarcadero.com/CodeExamples/XE7/en/GridLineWidth_%28C%2B%2B%29
void __fastcall TForm1::Button1Click(TObject *Sender) { if (DrawGrid1->DefaultColWidth > 90) DrawGrid1->GridLineWidth = 2; else DrawGrid1->GridLineWidth = 1; } void __fastcall TForm1::DrawGrid1DrawCell(TObject *Sender, int ACol, int ARow, TRect &Rect, TGridDrawState State) { int index = ARow * DrawGrid1->ColCount + ACol; DrawGrid1->Canvas->Brush->Color = clBackground; DrawGrid1->Canvas->FillRect(Rect); ImageList1->Draw(DrawGrid1->Canvas, Rect.Left, Rect.Top, index, True); if (State.Contains(gdFocused)) { DrawGrid1->Canvas->DrawFocusRect(Rect); } } void __fastcall TForm1::DrawGrid1SelectCell(TObject *Sender, int ACol, int ARow, bool &CanSelect) { CanSelect = True; }