private void serializeSample()
        {
            Person person1 = new Person();
            person1.Name = "山田太郎";
            person1.Age = 17;

            Person person2 = new Person();
            person2.Name = "山田二郎";
            person2.Age = 16;

            Person person3 = new Person();
            person3.Name = "山田三郎";
            person3.Age = 15;

            PersonCollection persons = new PersonCollection();
            persons.SetPersons( person1, person2, person3 );

            XmlSerializer serializer = new XmlSerializer(typeof(PersonCollection));
            using( FileStream stream = new FileStream(@"c:\sample.xml",FileMode.Create) )
            {
                serializer.Serialize(stream, persons);
            }
        }