Question

I use this code with TCheckListbox (lbServices) and it works fine. But with TcxCheckListBox from Devexpress it raise exception.

procedure TMaintenanceForm.AfterConstruction;
var
  i: Integer;
  ActionObj: TAction;
begin
  inherited;
  for i := 0 to ServiceActionList.ActionCount-1 do
  begin
    ActionObj := ServiceActionList.Actions[i] as TAction;
    lbServices.Items.AddObject(ActionObj.Caption, ActionObj);
  end;
end;

procedure TMaintenanceForm.btnStopClick(Sender: TObject);
begin
  fContinue := False;
end;

procedure TMaintenanceForm.cmdExecuteSelectedClick(Sender: TObject);
var
  i: Integer;
begin
  Screen.Cursor := crHourGlass;
  try
    for i := 0 to lbServices.Count -1 do
      if lbServices.Selected[i] then
        (lbServices.Items.Objects[i] as TAction).Execute;  // Exception here!!!!
  finally
    Screen.Cursor := crDefault;
  end;
end;

If I debug the code lbServices.Count = 12.
lbServices.Items.Objects[i] is nil for all items in the list. What is wrong here ?

Answer 1

Use the following code instead:

var
  AItem: TcxCheckListBoxItem;
begin
  AItem := cxCheckListBox1.Items.Add;
  AItem.ItemObject := Action1;
  AItem.Text := Action1.Caption;
end;

…

var
  I: Integer;
begin
  for I := 0 to cxCheckListBox1.Items.Count - 1 do
    if cxCheckListBox1.Items[I].Checked then
      (cxCheckListBox1.Items[I].ItemObject as TACtion).Execute;
end;