CheckedDropDownList adding checked items to the list in the code behind

Hi

I have been using a CheckedDropDownList in an application and I want to check some of the values in the dropdownlist before the users sees it. I have tried several things in order to get it work and so far nothing. It should b a simple thing i just don't know..

so far i have tried

 List<string> dbValues = _asset.MultiLocDrawingNum;

                    foreach (var v in dbValues)
                    {
                        var item = ddData.Items.FirstOrDefault(x => x.Text == v);

                        item.Selected = true;

                        ddData.Items.Add(item);

                        //ddData.SelectedItem = item;

                        //ddData.SelectedIndex = ddData.FindString(item.Text);
                    
                    
                    }