CPP file----------------------

//---------------------------------------------------------------------------
void __fastcall TForm1::CheckBoxMouseUp(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{
  TCheckBox* cbCheck = dynamic_cast<TCheckBox*>(Sender);
  cbCheck->Checked = !cbCheck->Checked;
  Checked[StrToInt(cbCheck->Caption)-1] = cbCheck->Checked;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormShow(TObject *Sender)
{
  tmp=StringGrid1->TopRow-1;
  for(int x=0;x<StringGrid1->VisibleRowCount;x++){
    t=new TCheckBox(this);
    StringGrid1->Objects[StringGrid1->TopRow+x][0] = t;
    t->Parent = StringGrid1;
    t->BoundsRect = StringGrid1->CellRect(1,StringGrid1->TopRow + x);
    t->OnMouseUp = CheckBoxMouseUp;
    t->Caption = IntToStr(StringGrid1->TopRow + x);
  }
}
//---------------------------------------------------------------------------
void __fastcall TForm1::StringGrid1TopLeftChanged(TObject *Sender)
{

  tmp=StringGrid1->TopRow-1;
  for(int x=0;x<StringGrid1->VisibleRowCount;x++){
    t=new TCheckBox(this);
    StringGrid1->Objects[StringGrid1->TopRow+x][0] = t;
    t->Parent = StringGrid1;
    t->BoundsRect = StringGrid1->CellRect(1,StringGrid1->TopRow+x);
    t->OnMouseUp = CheckBoxMouseUp;
    t->Caption = IntToStr(StringGrid1->TopRow+x);
    t->Checked=Checked[StrToInt(t->Caption)-1];
  }
}
//---------------------------------------------------------------------------


void __fastcall TForm1::FormClose(TObject *Sender, TCloseAction &Action)
{
  delete t;
}
//---------------------------------------------------------------------------

H file------------------------
class TForm1 : public TForm
{
__published:    // IDE-managed Components
  TStringGrid *StringGrid1;
  void __fastcall StringGrid1TopLeftChanged(TObject *Sender);
  void __fastcall CheckBoxMouseUp(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y);
  void __fastcall FormShow(TObject *Sender);
  void __fastcall FormClose(TObject *Sender, TCloseAction &Action);
private:    // User declarations
public:        // User declarations
  int tmp;
  TCheckBox *t;
  bool Checked[100];
  __fastcall TForm1(TComponent* Owner);
};
//---------------------------------------------------------------------------