Serialize into xml

serialize.cs

var serializer = new XmlSerializer(command.GetType());
MemoryStream stream = null;
try
{
    stream = new MemoryStream();
    var streamRef = stream;
    using (var writer = new XmlTextWriter(stream, Encoding.Unicode))
    {
        // stream is owned by writer and will be disposed automatically
        stream = null;
        serializer.Serialize(writer, command);
        var xml = Encoding.Unicode.GetString(streamRef.ToArray());
        var changeLog = new ChangeLog(principal, command.GetType(), xml);
        context.Changes.Add(changeLog);
    }
}
finally
{
    if (stream != null) stream.Dispose();
}