Question

I know that it doesn’t look like best practice but I need to generate xml with same namespaces

for example:

<ns1:root xsi:schemaLocation=""http://schemalocation""
xmlns:ns1=""http://schema""
xmlns:xsi=""http://www.w3.org/2001/XMLSchema-instance""
xmlns=""http://schema"">
...
</ns1:root>

I also added namespaces to serializer:

var xmlSerializerNamespaces = new XmlSerializerNamespaces();
xmlSerializerNamespaces.Add("ns1", "http://schema");
xmlSerializerNamespaces.Add("xsi", "http://www.w3.org/2001/XMLSchema-instance");
xmlSerializerNamespaces.Add(string.Empty, "http://schema");

And this is class itself:

[XmlRoot(ElementName = "request", Namespace = "http://schema")]
    [Serializable]
    public class Request 
    {
        [XmlAttributeAttribute("schemaLocation", Namespace = XmlSchema.InstanceNamespace)]
        public string SchemaLocation
        {
            get { return _schemaLocation; }
            set { _schemaLocation = value; }
        }

        ...

        private string _schemaLocation = "http://schemalocation";   }

So everything is great but default xmlns isn’t in generated xml.
I’ve also played with XmlWriterSettings with no result.
Have anybody ideas how to do it without string replacement?)

Answer 1

The default namespace is set based on which namespace you use to add the XML fragment e.g.

XNamespace defaultNs = @"http://schema";
var result = new XDocument(new XElement(defaultNs + "root"));

Would produce the following output:

<rootNode xmlns="http://schema">
</rootNode>

So all you have to do is add your other named ones to the document i.e.

XNamespace defaultNs = @"http://schema";
var root = new XElement(defaultNs + "root",
    new XAttribute("xsi", "schemaLocation", "http://schemaLocation"),
    new XAttribute(XNamespace.Xmlns + "ns1", defaultNs"),
    new XAttribute(XNamespace.Xmlns + "xsi", "http://www.w3.org/2001/XMLSchema-instance")
);