c# - Using StringWriter for XML Serialization

Question

I'm currently searching for an easy way to serialize objects (in C# 3).

I googled some examples and came up with something like:

MemoryStream memoryStream = new MemoryStream ( );
XmlSerializer xs = new XmlSerializer ( typeof ( MyObject) );
XmlTextWriter xmlTextWriter = new XmlTextWriter ( memoryStream, Encoding.UTF8 );
xs.Serialize ( xmlTextWriter, myObject);
string result = Encoding.UTF8.GetString(memoryStream .ToArray());

After reading this question I asked myself, why not using StringWriter? It seems much easier.

XmlSerializer ser = new XmlSerializer(typeof(MyObject));
StringWriter writer = new StringWriter();
ser.Serialize(writer, myObject);
serializedValue = writer.ToString();

Another Problem was, that the first example generated XML I could not just write into an XML column of SQL Server 2005 DB.

The first question is: Is there a reason why I shouldn't use StringWriter to serialize an Object when I need it as a string afterwards? I never found a result using StringWriter when googling.

The second is, of course: If you should not do it with StringWriter (for whatever reasons), which would be a good and correct way?

---

Addition:

As it was already mentioned by both answers, I'll further go into the XML to DB problem.

When writing to the Database I got the following exception:

System.Data.SqlClient.SqlException: XML parsing: line 1, character 38, unable to switch the encoding

For string

<?xml version="1.0" encoding="utf-8"?><test/>

I took the string created from the XmlTextWriter and just put as xml there. This one did not work (neither with manual insertion into the DB).

Afterwards I tried manual insertion (just writing INSERT INTO ... ) with encoding="utf-16" which also failed. Removing the encoding totally worked then. After that result I switched back to the StringWriter code and voila - it worked.

Problem: I don't really understand why.

at Christian Hayter: With those tests I'm not sure that I have to use utf-16 to write to the DB. Wouldn't setting the encoding to UTF-16 (in the xml tag) work then?

Answer 1

One problem with StringWriter is that by default it doesn't let you set the encoding which it advertises - so you can end up with an XML document advertising its encoding as UTF-16, which means you need to encode it as UTF-16 if you write it to a file. I have a small class to help with that though:

public sealed class StringWriterWithEncoding : StringWriter
{
    public override Encoding Encoding { get; }

    public StringWriterWithEncoding (Encoding encoding)
    {
        Encoding = encoding;
    }    
}

Or if you only need UTF-8 (which is all I often need):

public sealed class Utf8StringWriter : StringWriter
{
    public override Encoding Encoding => Encoding.UTF8;
}

As for why you couldn't save your XML to the database - you'll have to give us more details about what happened when you tried, if you want us to be able to diagnose/fix it.