Question

I’m trying to insert into XML column (SQL SERVER 2008 R2), but the server’s complaining:

System.Data.SqlClient.SqlException (0x80131904):
XML parsing: line 1, character 39, unable to switch the encoding

I found out that the XML column has to be UTF-16 in order for the insert to succeed.

The code I’m using is:

 XmlSerializer serializer = new XmlSerializer(typeof(MyMessage));
 StringWriter str = new StringWriter();
 serializer.Serialize(str, message);
 string messageToLog = str.ToString();

How can I serialize object to be in UTF-8 string?

EDIT: Ok, sorry for the mixup – the string needs to be in UTF-8. You were right – it’s UTF-16 by default, and if I try to insert in UTF-8 it passes. So the question is how to serialize into UTF-8.

Example

This causes errors while trying to insert into SQL Server:

    <?xml version="1.0" encoding="utf-16"?>
    <MyMessage>Teno</MyMessage>

This doesn’t:

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

Update

I figured out when the SQL Server 2008 for its Xml column type needs utf-8, and when utf-16 in encoding property of the xml specification you’re trying to insert:

When you want to add utf-8, then add parameters to SQL command like this:

 sqlcmd.Parameters.Add("ParamName", SqlDbType.VarChar).Value = xmlValueToAdd;

If you try to add the xmlValueToAdd with encoding=utf-16 in the previous row it would produce errors in insert. Also, the VarChar means that national characters aren’t recognized (they turn out as question marks).

To add utf-16 to db, either use SqlDbType.NVarChar or SqlDbType.Xml in previous example, or just don’t specify type at all:

 sqlcmd.Parameters.Add(new SqlParameter("ParamName", xmlValueToAdd));

Answer 1

Although a .net string is always UTF-16 you need to serialize the object using UTF-16 encoding.
That sould be something like this:

public static string ToString(object source, Type type, Encoding encoding)
{
    // The string to hold the object content
    String content;

    // Create a memoryStream into which the data can be written and readed
    using (var stream = new MemoryStream())
    {
        // Create the xml serializer, the serializer needs to know the type
        // of the object that will be serialized
        var xmlSerializer = new XmlSerializer(type);

        // Create a XmlTextWriter to write the xml object source, we are going
        // to define the encoding in the constructor
        using (var writer = new XmlTextWriter(stream, encoding))
        {
            // Save the state of the object into the stream
            xmlSerializer.Serialize(writer, source);

            // Flush the stream
            writer.Flush();

            // Read the stream into a string
            using (var reader = new StreamReader(stream, encoding))
            {
                // Set the stream position to the begin
                stream.Position = 0;

                // Read the stream into a string
                content = reader.ReadToEnd();
            }
        }
    }

    // Return the xml string with the object content
    return content;
}

By setting the encoding to Encoding.Unicode not only the string will be UTF-16 but you should also get the xml string as UTF-16.

<?xml version="1.0" encoding="utf-16"?>