procedure TForm1.FormCreate(Sender: TObject);
begin
  ComboBox1.Clear;
  ComboBox1.Style := csOwnerDrawFixed;
  ComboBox1.Items.Add('cmd_estart=Entry start');
  ComboBox1.Items.Add('cmd_eend=Entry End');
end;

procedure TForm1.ComboBox1DrawItem(Control: TWinControl; Index: Integer; Rect: TRect; State: TOwnerDrawState);
begin
  TComboBox(Control).Canvas.FillRect(Rect);
  if Index >= 0 then
    TComboBox(Control).Canvas.TextOut(Rect.Left + 2, Rect.Top, TComboBox(Control).Items.ValueFromIndex[Index]);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  ItemCommand: string;
  ItemCaption: string;
begin
  ItemCommand := ComboBox1.Items.Names[ComboBox1.ItemIndex];
  ItemCaption := ComboBox1.Items.ValueFromIndex[ComboBox1.ItemIndex];
  ShowMessage(Format('Command: %s; Caption: %s', [ItemCommand, ItemCaption]));
end;