Why doesn't XmlSerializer support Dictionary?

Hashtables need hashcode and equality comparer providers generally. These cant be serialized easily in XML, and definitely will not be portable.

But I think you already found your answer. Just serialize the hashtable as a List<KeyValuePair<K,V>> and then (re)construct it into a hashtable.

This is waaay late - but I found this question whilst looking for the answer myself, and thought I'd share my eventual answer which was to replace XmlSerializer with a different tool that will serialize everything:

http://www.sharpserializer.com

It worked for me straight out of the box, serializing Dictionaries, and multi-layered custom types, and even generics using interfaces as type arguments. Also has a fully permissive license.

Thank you Pawel Idzikowski!

You can use ExtendedXmlSerializer. If you have a class:

public class TestClass{    public Dictionary<int, string> Dictionary { get; set; }}

and create instance of this class:

var obj = new TestClass{    Dictionary = new Dictionary<int, string>    {        {1, "First"},        {2, "Second"},        {3, "Other"},    }};

You can serialize this object using ExtendedXmlSerializer:

var serializer = new ConfigurationContainer()    .UseOptimizedNamespaces() //If you want to have all namespaces in root element    .Create();var xml = serializer.Serialize(    new XmlWriterSettings { Indent = true }, //If you want to formated xml    obj);

Output xml will look like:

<?xml version="1.0" encoding="utf-8"?><TestClass xmlns:sys="https://extendedxmlserializer.github.io/system" xmlns:exs="https://extendedxmlserializer.github.io/v2" xmlns="clr-namespace:ExtendedXmlSerializer.Samples;assembly=ExtendedXmlSerializer.Samples">  <Dictionary>    <sys:Item>      <Key>1</Key>      <Value>First</Value>    </sys:Item>    <sys:Item>      <Key>2</Key>      <Value>Second</Value>    </sys:Item>    <sys:Item>      <Key>3</Key>      <Value>Other</Value>    </sys:Item>  </Dictionary></TestClass>

You can install ExtendedXmlSerializer from nuget or run the following command:

Install-Package ExtendedXmlSerializer