private void LoadLangs()
        {
            this.Langs.Clear();
            DbSet<PrfLang> langs = this.DataService.GetDbSet<PrfLang>();

            List<String> codeIsos = (from l in langs select l.CodeIso).Distinct().ToList();

            String defaultCodeIso = "fra";
            DbSet<PrfParam> parameters = this.DataService.GetDbSet<PrfParam>();
            PrfParam paramDefaultLang = (from p in parameters where p.Code.Equals("LANG") select p).FirstOrDefault();
            if (paramDefaultLang == null)
            {
                PrfParam param = new PrfParam();
                param.Code = "LANG";
                param.Valeur = "fra";
                parameters.Add(param);
                this.DataService.DataContext.SaveChanges();
            }
            else
            { defaultCodeIso = paramDefaultLang.Valeur; }

            foreach (String codeIso in codeIsos)
            {
                LangViewModel vm = new LangViewModel();
                vm.CodeIso = codeIso;
                vm.DisplayName = codeIso;
                this.Langs.Add(vm);
                if (codeIso.Equals(defaultCodeIso))
                {
                    this._selectedLang = vm;
                    this.RaisePropertyChanged("SelectedLang");
                }
            }
        }
        private void ChangeCurrentLang()
        {
            DbSet<PrfParam> parameters = this.DataService.GetDbSet<PrfParam>();

            List<PrfParam> itemToRemoves = (from p in parameters where p.Code.Equals("LANG") select p).ToList ();
            foreach (PrfParam itemToRemove in itemToRemoves)
            {parameters.Remove(itemToRemove);}
            this.DataService.DataContext.SaveChanges();

            if (this._selectedLang != null)
            {
                PrfParam param = new PrfParam();
                param.Code = "LANG";
                param.Valeur = this._selectedLang.CodeIso;
                parameters.Add(param);
                this.DataService.DataContext.SaveChanges();
                ServiceLocator.Current.GetInstance<ITranslateService>().LoadCurrentLang();
            }
        }