遍历寻找json中的重复数据

string str = "[{"ID":1,"Data":{"subjectCode":"1","subjectName":"1","subjectType":"1","componentFormat":"2"}},{"ID":2,"Data":{"subjectCode":"1","subjectName":"2","subjectType":"1","componentFormat":"2"}},{"ID":4,"Data":{"subjectCode":"1","subjectName":"1","subjectType":"1","componentFormat":"2"}}]";
            JavaScriptSerializer jss = new JavaScriptSerializer();
            List<A> aList = jss.Deserialize<List<A>>(str);
            for (int i = 0; i < aList.Count - 1; i++)
            {
                int index = i + 1;
                A a = aList[i];
                while (index < aList.Count)
                {
                    A b = aList[index];
                    if (a.Data.subjectCode.Equals(b.Data.subjectCode) && a.Data.subjectName.Equals(b.Data.subjectName) && a.Data.subjectType.Equals(b.Data.subjectType) && a.Data.componentFormat.Equals(b.Data.componentFormat))
                    {
                        string message = a.ID + "=" + b.ID;
                        Console.WriteLine(message);
                        break;
                    }
                    index++;
                }
            }
            Console.ReadKey();
        }

        public class A
        {
            public int ID { get; set; }
            public B Data { get; set; }
        }

        public class B
        {
            public string subjectCode { get; set; }
            public string subjectName { get; set; }
            public string subjectType { get; set; }
            public string componentFormat { get; set; }
        }