public JsonResult ChildrenCategories(int IDParent, string IDChilrenCategories) { var list = new CategoryModel().GetAll().Where(x => x.IDParent == IDParent); string[] listSelectCategories = null; if (IDChilrenCategories != "NaN") { listSelectCategories = IDChilrenCategories.Split(','); } var listIDCategories = new List <int>(); if (listSelectCategories != null) { foreach (var item in listSelectCategories) { listIDCategories.Add(Int32.Parse(item)); } } var listDrop = new List <DropListItem>(); list.ForEach(item => listDrop.Add(new DropListItem(item.Name, item.ID.GetValueOrDefault(0), listIDCategories.Exists(item1 => item1 == item.ID)))); return(Json(new { list = new JavaScriptSerializer().Serialize(listDrop) })); }