Question

My data entity contains a Dictionary, but XmlSerializer does not support them out of the box. So I decided to use DataContractSerializer. The problem is that I cannot get it to behave as I need.

I started with the following code:

public static string SerializeObject<T>(T serialisable)
{
    var serializer = new DataContractSerializer(serialisable.GetType());
    using (var writer = new StringWriter())
    using (var stm = new XmlTextWriter(writer))
    {
        serializer.WriteObject(stm, serialisable);
        return writer.ToString();
    }
}

It seemed to work fine until I noticed that if I put “\r\n” in a string, it does not get serialized to XML entities. From my experience with XmlSerializer, I knew that I can set up XmlWriterSettings with NewLineHandling = NewLineHandling.Entitize. So I converted my code to the following:

public static string SerializeObject<T>(T serialisable)
{
    var serializer = new DataContractSerializer(serialisable.GetType());
    using (var writer = new StringWriter())
    {
        using (var stm = XmlWriter.Create(writer,
            new XmlWriterSettings()
            {
                NewLineHandling = NewLineHandling.Entitize
            }))
        {
            serializer.WriteObject(stm, serialisable);
            return writer.ToString();
        }
    }
}

Now the problem is that I get an empty string. No exceptions, nothing – just an empty string.
The stm variable holds XmlWellFormedWriter. Maybe it’s not supported by DataContractSerializer?

Then I tried to enforce XmlTextWriter as follows:

public static string SerializeObject<T>(T serialisable)
{
    var serializer = new DataContractSerializer(serialisable.GetType());
    using (var writer = new StringWriter())
    using (var stm = XmlWriter.Create(new XmlTextWriter(writer),
        new XmlWriterSettings()
        {
            NewLineHandling = NewLineHandling.Entitize
        }))
    {
        serializer.WriteObject(stm, serialisable);
        return writer.ToString();
    }
}

And this gets me back to where I started – I get back XML string, but again “\r\n” string is not translated to entities.

How do I make DataContractSerializer to entitize newlines and return XML as string?

Answer 1

It seems, the problem is mostly because of how disposing XmlWriter works – if I create it with XmlWriter.Create, it does not flush until it’s closed, so the StringWriter is empty. What’s weird – if I create it with new XmlTextWriter, it somehow flushes its contents to the StringWriter, so my initial method worked just fine.

This time I just had to rearrange one line of code:

    public static string SerializeObject<T>(T serialisable)
    {
        var serializer = new DataContractSerializer(serialisable.GetType());
        using (var writer = new StringWriter())
        {
            using (var stm = XmlWriter.Create(writer,
                new XmlWriterSettings()
                {
                    NewLineHandling = NewLineHandling.Entitize,
                    Encoding = UTF8Encoding.UTF8
                }))
            {
                serializer.WriteObject(stm, serialisable);
                // <- previously writer.ToString() was here and I got an empty string
            }     

            return writer.ToString();
        }
    }

Now “\r” characters are encoded correctly as 
, but “\n” are not. And encoding is still utf-16, although I set it to UTF8. I guess, that’s another issue.