问在XmlSerializer中缓存AppDomain

EN

public static class XmlSerializerCache
{
    public static XmlSerializer GetXmlSerializer(Type type, XmlRootAttribute xmlRoot)
    {
        var cache = System.AppDomain.CurrentDomain;
        var key = String.Format(CultureInfo.InvariantCulture, "CachedXmlSerializer:{0}:{1}", type, xmlRoot.ElementName);

        var serializer = cache.GetData(key) as XmlSerializer;
        if (serializer == null)
        {
            serializer = new XmlSerializer(type, xmlRoot);
            cache.SetData(key, serializer);
        }
        return serializer;
    }
}