How can I serialize an object with a Dictionary<string,object> property?

Question

In the example code below, I get this error:

Element TestSerializeDictionary123.Customer.CustomProperties vom Typ System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Object, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] can not be serialized because it implements IDictionary.

When I take out the Dictionary property, it works fine.

How can I serialize this Customer object with the dictionary property? Or what replacement type for Dictionary can I use that would be serializable?

using System;
using System.Collections.Generic;
using System.Xml.Serialization;
using System.IO;
using System.Xml;
using System.Text;

namespace TestSerializeDictionary123
{
    public class Program
    {
        static void Main(string[] args)
        {
            List<Customer> customers = Customer.GetCustomers();

            Console.WriteLine("--- Serializing ------------------");

            foreach (var customer in customers)
            {
                Console.WriteLine("Serializing " + customer.GetFullName() + "...");
                string xml = XmlHelpers.SerializeObject<Customer>(customer);
                Console.WriteLine(xml);
                Console.WriteLine("Deserializing ...");
                Customer customer2 = XmlHelpers.DeserializeObject<Customer>(xml);
                Console.WriteLine(customer2.GetFullName());
                Console.WriteLine("---");
            }

            Console.ReadLine();
        }
    }

    public static class StringHelpers
    {
        public static String UTF8ByteArrayToString(Byte[] characters)
        {
            UTF8Encoding encoding = new UTF8Encoding();
            String constructedString = encoding.GetString(characters);
            return (constructedString);
        }

        public static Byte[] StringToUTF8ByteArray(String pXmlString)
        {
            UTF8Encoding encoding = new UTF8Encoding();
            Byte[] byteArray = encoding.GetBytes(pXmlString);
            return byteArray;
        }
    }

    public static class XmlHelpers
    {
        public static string SerializeObject<T>(object o)
        {
            MemoryStream ms = new MemoryStream();
            XmlSerializer xs = new XmlSerializer(typeof(T));
            XmlTextWriter xtw = new XmlTextWriter(ms, Encoding.UTF8);
            xs.Serialize(xtw, o);
            ms = (MemoryStream)xtw.BaseStream;
            return StringHelpers.UTF8ByteArrayToString(ms.ToArray());
        }

        public static T DeserializeObject<T>(string xml)
        {
            XmlSerializer xs = new XmlSerializer(typeof(T));
            MemoryStream ms = new MemoryStream(StringHelpers.StringToUTF8ByteArray(xml));
            XmlTextWriter xtw = new XmlTextWriter(ms, Encoding.UTF8);
            return (T)xs.Deserialize(ms);
        }
    }

    public class Customer
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Street { get; set; }
        public string Location { get; set; }
        public string ZipCode { get; set; }
        public Dictionary<string,object> CustomProperties { get; set; }

        private int internalValue = 23;

        public static List<Customer> GetCustomers()
        {
            List<Customer> customers = new List<Customer>();
            customers.Add(new Customer { Id = 1, FirstName = "Jim", LastName = "Jones", ZipCode = "23434" });
            customers.Add(new Customer { Id = 2, FirstName = "Joe", LastName = "Adams", ZipCode = "12312" });
            customers.Add(new Customer { Id = 3, FirstName = "Jack", LastName = "Johnson", ZipCode = "23111" });
            customers.Add(new Customer { Id = 4, FirstName = "Angie", LastName = "Reckar", ZipCode = "54343" });
            customers.Add(new Customer { Id = 5, FirstName = "Henry", LastName = "Anderson", ZipCode = "16623" });
            return customers;
        }

        public string GetFullName()
        {
            return FirstName + " " + LastName + "(" + internalValue + ")";
        }

    }
}

Answer 1

In our application we ended up using:

DataContractSerializer xs = new DataContractSerializer(typeof (T));

instead of:

XmlSerializer xs = new XmlSerializer(typeof (T));

which solved the problem as DatacontractSerializer supports Dictionary.

Another solution is ths XML Serializable Generic Dictionary workaround also works in the above example, and there is a long discussion at that link from people using it, might be useful for people working with this issue.