Dictionaryをシリアル化する（XMLファイルに保存） ref: http://qiita.com/items/b88a5da3965a1c5bed0d

DeSerialize.cs

XmlSerializer serializer = new XmlSerializer(typeof(RecordInfo));
RecordInfo record2 = new RecordInfo();
using (FileStream fs = new FileStream(GetXMLFilePath(), FileMode.Open))
{
    record2 = serializer.Deserialize(fs) as RecordInfo;
    // XML からオブジェクトが復元されている
}

FieldInfo.cs

public class FieldInfo
{
    public FieldInfo(string FieldName, string JapaneseFieldName)
    {
        this.FieldName = FieldName;
        this.JapaneseFieldName = JapaneseFieldName;
    }

    public string FieldName;
    public string JapaneseFieldName;
}

Main.cs

private void Form1_Load(object sender, EventArgs e)
{
    record = new RecordInfo();

    record.Add("key1", new FieldInfo("key1", "キー１"));
    record.Add("key2", new FieldInfo("key2", "キー２"));
}

private string GetXMLFilePath()
{
    return @"d:\test.xml";
}

RecordInfo.cs

// これは私が必要だったので作ったクラス。作成する必要はない
public class RecordInfo: SerializableDictionary<string, FieldInfo>
{
}

SerializableDictionary.cs.cs

// シリアル化可能な Dictionary クラス
public class SerializableDictionary<Tkey, TValue> : Dictionary<Tkey, TValue>, IXmlSerializable
{
    public System.Xml.Schema.XmlSchema GetSchema()
    {
        return null;
    }

    public void ReadXml(XmlReader reader)
    {
        XmlSerializer serializer = new XmlSerializer(typeof(KeyValue));

        reader.Read();
        if (reader.IsEmptyElement)
            return;

        while (reader.NodeType != XmlNodeType.EndElement)
        {
            KeyValue kv = serializer.Deserialize(reader) as KeyValue;
            if (kv != null) 
                Add(kv.Key, kv.Value);
        }
        reader.Read();
    }

    public void WriteXml(XmlWriter writer)
    {
        XmlSerializer serializer = new XmlSerializer(typeof(KeyValue));
        foreach (var key in Keys)
        {
            serializer.Serialize(writer, new KeyValue(key, this[key]));
        }
    }

    public class KeyValue
    {
        public KeyValue(Tkey key, TValue value)
        {
            Key = key;
            Value = value;
        }

        public Tkey Key { get; set; }
        public TValue Value { get; set; }
    }
}

Serialize.cs

var selializer = new XmlSerializer(typeof(RecordInfo));
using (FileStream fs = new FileStream(GetXMLFilePath(), FileMode.Create))
{
    selializer.Serialize(fs, record);
}