Question

I have a class containing a SortedList<string, Data> as private field, where Data is a simple custom class with some int, DateTime and Nullable<DateTime> fields.

public class CustomCollection
{
    private SortedList<string, Data> _list;

    ...
}

Now I would make my class serializable, so I could write its content (ie the items of the _list field) in an XML file or load data from an existing XML file.

How should I proceed?

I think I understand that there are two ways to serialize: the first would be to mark all fields as serializable, while the second would be to implement the IXmlSerializable interface. If I understand correctly, when I can use each of the two ways?

Answer 1

Ok, you just need to decorate your Classes with [Serializable] attribute and it should work. However you have a SortedList which implements an IDictionary and these cant be serialized with the IXMLSerializable so need to do a bit of customization look here

Serializing .NET dictionary

but if you change your sorted list to a normal list or anything that doesnt implement an IDictionary then the below code will work 🙂 copy it to a console app and run it.

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Data d = new Data { CurrentDateTime = DateTime.Now, DataId = 1 };
            Data d1 = new Data { CurrentDateTime = DateTime.Now, DataId = 2 };
            Data d2 = new Data { CurrentDateTime = DateTime.Now, DataId = 3 };

            CustomCollection cc = new CustomCollection
                                      {List = new List<Data> {d, d1, d2}};

            //This is the xml
            string xml = MessageSerializer<CustomCollection>.Serialize(cc);

            //This is deserialising it back to the original collection
            CustomCollection collection = MessageSerializer<CustomCollection>.Deserialize(xml);
        }
    }

    [Serializable]
    public class Data
    {
        public int DataId;
        public DateTime CurrentDateTime;
        public DateTime? CurrentNullableDateTime;
    }

    [Serializable]
    public class CustomCollection
    {
        public List<Data> List;
    }

    public class MessageSerializer<T>
    {
        public static T Deserialize(string type)
        {
            var serializer = new XmlSerializer(typeof(T));

            var result = (T)serializer.Deserialize(new StringReader(type));

            return result;
        }

        public static string Serialize(T type)
        {
            var serializer = new XmlSerializer(typeof(T));
            string originalMessage;

            using (var ms = new MemoryStream())
            {
                serializer.Serialize(ms, type);
                ms.Position = 0;
                var document = new XmlDocument();
                document.Load(ms);

                originalMessage = document.OuterXml;
            }

            return originalMessage;
        }
    }
}