1.第一种方式if(partsSalesOrderTypes.GroupBy(entity => new {                    entity.Name,                    entity.Code                }).Any(array => array.Count() > 1)) {                    /*违反多字段唯一时，提示信息处理*/ return;}2.第二种方式var groupPrice = from price in this.PartsSpecialTreatyPrices                               group price by new {                                       price.DealerId,     //分组字段                                       price.PartsSalesCategoryId,    //分组字段                                       price.SparePartId    //分组字段                               }                                       into groups                                       select new {                                               count = groups.Count(),                                               key = groups.Key                                       };if(groupPrice.Any(group => group.count > 1)) {     /*违反多字段唯一时，提示信息处理*/}