public NsnCatalogItemViewModel CreateNsnCatalogItemViewModel()
        {
            NsnCatalogItemViewModel vm = new NsnCatalogItemViewModel();

            vm.ItemClasses = db.ItemClasses.ToList();
            vm.UnitIssues = db.UnitIssues.ToList();

            return vm;
        }
        private NsnCatalogItem ConvertNsnCatalogItemViewModelToModel(NsnCatalogItemViewModel vm)
        {
            NsnCatalogItem model = new NsnCatalogItem
            {

            };

            return model;
        }