Change DropDown Multiselect values from code

sending code in attachment

![function to set dropdown|436x500, 100%]
protected void BindModelValue(string control)
{

            case "region":

                region = !region;
                userAccessModel.AccessLevel = 1;
                if (region)
                {
                    loc = false;
                    mc = false;
                    CurrentUserAccess.MCs = new List<string>() { "11111" };
                    CurrentUserAccess.Locs = new List<string>() { "11111" };
                    CurrentUserAccess.Depts = new List<string>() { "1111" };                        

                }
                break;
            case "mc":
                mc = !mc;
                if (mc)
                {
                    
                    loc = false;
                    region = false;
                    
                    CurrentUserAccess.MCs= new List<string>();

CurrentUserAccess.Locs = new List() { "11111"}; CurrentUserAccess.Depts = new List() { "1111" };
}

                break;
            case "loc":

                loc = !loc;
                if (loc)
                {
                    mc = false;
                    region = false;
                    CurrentUserAccess.MCs = new List<string>();
                    CurrentUserAccess.Locs= new List<string>();
                    CurrentUserAccess.Depts = new List<string>() { "1111" } ;


                }

                break;


        }


    }