Serializing a list of Key/Value pairs to XML

Question

I have a list of key/value pairs I'd like to store in and retrieve from a XML file. So this task is similar as described here. I am trying to follow the advice in the marked answer (using a KeyValuePair and a XmlSerializer) but I don't get it working.

What I have so far is a "Settings" class ...

public class Settings {     public int simpleValue;     public List<KeyValuePair<string, int>> list; } 

... an instance of this class ...

Settings aSettings = new Settings();  aSettings.simpleValue = 2;  aSettings.list = new List<KeyValuePair<string, int>>(); aSettings.list.Add(new KeyValuePair<string, int>("m1", 1)); aSettings.list.Add(new KeyValuePair<string, int>("m2", 2)); 

... and the following code to write that instance to a XML file:

XmlSerializer serializer = new XmlSerializer(typeof(Settings)); TextWriter writer = new StreamWriter("c:\\testfile.xml"); serializer.Serialize(writer, aSettings); writer.Close(); 

The resulting file is:

<?xml version="1.0" encoding="utf-8"?> <Settings xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">   <simpleValue>2</simpleValue>   <list>     <KeyValuePairOfStringInt32 />     <KeyValuePairOfStringInt32 />   </list> </Settings> 

So neither key nor value of the pairs in my list are stored though the number of elements is correct. Obviously I am doing something basically wrong. My questions are:

• How can I store the key/value pairs of the list in the file?
• How can I change the default generated name "KeyValuePairOfStringInt32" of the elements in the list to some other name like "listElement" I'd like to have?

Answer 1

KeyValuePair is not serializable, because it has read-only properties. Here is more information(thanks to Thomas Levesque). For changing the generated name use the [XmlType] attribute.

Define your own like this:

[Serializable] [XmlType(TypeName="WhateverNameYouLike")] public struct KeyValuePair<K, V> {   public K Key    { get; set; }    public V Value    { get; set; } }