procedure TForm1.DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;
  DataCol: Integer; Column: TColumn; State: TGridDrawState);
begin
if (gdFocused in State) then
  begin
    if (Column.Field.FieldName = DBLookupComboBox1.DataField) then
    with DBLookupComboBox1 do
    begin
      Left := Rect.Left + DBGrid1.Left + 2;
      Top := Rect.Top + DBGrid1.Top + 2;
      Width := Rect.Right - Rect.Left;
      Width := Rect.Right - Rect.Left;
      Height := Rect.Bottom - Rect.Top;
      Visible := True;
    end;
  end
end;
procedure TForm1.DBGrid1ColExit(Sender: TObject);
begin
if DBGrid1.SelectedField.FieldName = DBLookupComboBox1.DataField then
    DBLookupComboBox1.Visible := False
end;
procedure TForm1.DBGrid1KeyPress(Sender: TObject; var Key: Char);
begin
if (key = Chr(9)) then Exit;
  if (DBGrid1.SelectedField.FieldName = DBLookupComboBox1.DataField) then
  begin
    DBLookupComboBox1.SetFocus;
    SendMessage(DBLookupComboBox1.Handle, WM_Char, word(Key), 0);
  end
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
  dblookupcombobox1.visible := false;
  dblookupcombobox1.DropDownWidth := 250;
  dblookupcombobox1.Color := clMoneyGreen;
end;