unit Unit1;
interface
uses
 Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
 Grids, StdCtrls;
type
 TForm1 = class(TForm)
  StringGrid1: TStringGrid;
  procedure StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
  procedure FormCreate(Sender: TObject);
 private
  { Private declarations }
 public
  { Public declarations }
 end;
const
 cell_x = 2;
 cell_y = 2;
var
 Form1: TForm1;
 CheckBox1: TCheckBox;
implementation
{$R *.DFM}
procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
 Rect: TRect; State: TGridDrawState);
var
 r:trect;
begin
 if(cell_x>=StringGrid1.LeftCol) and
  (cell_x<=StringGrid1.LeftCol+StringGrid1.VisibleColCount) and
  (cell_y>=StringGrid1.Row) and
  (cell_x<=StringGrid1.Row+StringGrid1.VisibleRowCount) then
  CheckBox1.Visible:=true
 else
  CheckBox1.Visible:=false;
 if (acol=cell_x) and (arow=cell_y) then
 begin
  r:=stringgrid1.CellRect(cell_x,cell_y);
  r.Left:=r.left+stringgrid1.left+2;
  r.right:=r.right+stringgrid1.left+2;
  r.top:=r.top+stringgrid1.top+2;
  r.bottom:=r.bottom+stringgrid1.top+2;
  CheckBox1.BoundsRect:=r;
 end;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
 CheckBox1:=TCheckBox.Create(form1);
 CheckBox1.parent:=form1;
 CheckBox1.Caption:='proba';
end;
end.

procedure TForm1.CheckBox1Click(Sender: TObject);

begin

 ShowMessage('There it is!!');

end;

// Заполняем заголовок StringGrid

procedure TForm1.FormCreate(Sender: TObject);

begin

 StringGrid1.Cells[0, 0] := 'A Simple';

 StringGrid1.Cells[1, 0] := 'Way';

 StringGrid1.Cells[2, 0] := 'To';

 StringGrid1.Cells[3, 0] := 'Do It';

 StringGrid1.Cells[4, 0] := 'Check !!';

 AddCheckBoxes; // добавляем чекбоксы...

end;

procedure TForm1.AddCheckBoxes;

var

 i: Integer;

 NewCheckBox: TCheckBox;

begin

 clean_previus_buffer; // очищаем неиспользуемые чекбоксы...

 for i := 1 to 4 do

 begin

  StringGrid1.Cells[0, i] := 'a';

  StringGrid1.Cells[1, i] := 'b';

  StringGrid1.Cells[2, i] := 'c';

  StringGrid1.Cells[3, i] := 'd';

  NewCheckBox := TCheckBox.Create(Application);

  NewCheckBox.Width := 0;

  NewCheckBox.Visible := false;

  NewCheckBox.Caption := 'OK';

  NewCheckBox.Color := clWindow;

  NewCheckBox.Tag := i;

  NewCheckBox.OnClick := CheckBox1.OnClick; // Связываем предыдущее событие OnClick

  // с существующим TCheckBox

  NewCheckBox.Parent := Panel1;

  StringGrid1.Objects[4, i] := NewCheckBox;

  StringGrid1.RowCount := i;

 end;

 set_checkbox_alignment; // расположение чекбоксов в ячейках таблицы...

end;

procedure TForm1.clean_previus_buffer;

var

 NewCheckBox: TCheckBox;

 i: Integer;

begin

 for i := 1 to StringGrid1.RowCount do

 begin

  NewCheckBox := (StringGrid1.Objects[4, i] as TCheckBox);

  if NewCheckBox <> nil then

  begin

  NewCheckBox.Visible := false;

  StringGrid1.Objects[4, i] := nil;

  end;

 end;

end;

procedure TForm1.set_checkbox_alignment;

var

 NewCheckBox: TCheckBox;

 Rect: TRect;

 i: Integer;

begin

 for i := 1 to StringGrid1.RowCount do

 begin

  NewCheckBox := (StringGrid1.Objects[4, i] as TCheckBox);

  if NewCheckBox <> nil then

  begin

  Rect := StringGrid1.CellRect(4, i); // получаем размер ячейки для чекбокса

  NewCheckBox.Left := StringGrid1.Left + Rect.Left + 2;

  NewCheckBox. := StringGrid1. + Rect. + 2;

  NewCheckBox.Width := Rect.Right - Rect.Left;

  NewCheckBox.Height := Rect.Bottom - Rect.;

  NewCheckBox.Visible := True;

  end;

 end;

end;

procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;

 Rect: TRect; State: TGridDrawState);

begin

 if not (gdFixed in State) then

  set_checkbox_alignment;

end;