Question

I am using the XmlWriter in conjunction with Xml Serialization. I am able to output the XML fine, but how to include the xmlns attribute with the XmlWriter seems to be escaping me.

To write the start of the document I use the following:

    Writer.WriteStartDocument();     Writer.WriteStartElement('urlset','http://www.sitemaps.org/schemas/sitemap/0.9'); 

With my XmlWriter created I then loop through SitemapNodes I have created them and write them to the underlying stringbuilder through serialization like this:

    foreach (uk.co.andrewrea.SitemapNode node in List)     {         Serializer.Serialize(Writer, node);     } 

As I say this works fine BUT the above namespace for the root element is not included. Every time I try to physically write the attribute, xmlns, I get an exception that the xmlns is reserved by the system for XML use, so basically I cannot use.

I know how to do this using the XmlTextWriter and also using the XmlDocument class but i need to understand how I achieve this using the XmlWriter and through Serialization.

The following attempt also throws the exception about that namespace being reserved.

foreach (uk.co.andrewrea.SitemapNode node in List) {       XmlSerializerNamespaces ns = new XmlSerializerNamespaces();       ns.Add('xmlns', 'http://www.sitemaps.org/schemas/sitemap/0.9');        Serializer.Serialize(Writer, node, ns); }  Exception Details: System.ArgumentException: Prefix 'xmlns' is reserved for use by XML. 

Answer 1

You can add the namespace to the XmlSerialization attributes, e.g.:

[XmlElement( ElementName = 'Members', Namespace = 'http://www.cpandl.com')] public Employee[] Employees; 

if you have control over the code.