How to add namespaces to XML before serialization-CodePudding

I do have a problem with serialization of a namespaces. As my code show below my logic fills the structure of my dictionary, serializes it and puts into a string variable. I use this variable to load into XMLDocument and after that I do add the namespaces. But since they are added after the serialization process the namespaces are set in UTF8? Should I add namespaces before serialization? If yes, how can I do it properly?

///Dictionary
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml.Serialization;

namespace TestXML
{
[Serializable]
[XmlRoot(ElementName = "Root")]
public class XMLSchema: Serialization
{
    [XmlElement(ElementName = "Element1")]
    public XMLElement1 Element1 { get; set; }

    [XmlElement(ElementName = "Element2")]
    public XMLElement2 Element2 { get; set; }

}
}


 ///Serialization class
 public class Utf8StringWriter : StringWriter
    {
        // Use UTF8 encoding 
        public override Encoding Encoding
        {
            get { return new UTF8Encoding(false); } 
        }
    }

    public string Serialize()
    {
        var xmlserializer = new XmlSerializer(this.GetType());
        var Utf8StringWriter = new Utf8StringWriter();
        var xns = new XmlSerializerNamespaces();
        xns.Add(string.Empty, string.Empty);

        using (var writer = XmlWriter.Create(Utf8StringWriter))
        {
            xmlserializer.Serialize(writer, this, xns);
          return Utf8StringWriter.ToString();
        }
    }


    ///create xml
            str xml;
            [...] my logic to add data into elements
            XmlDocument doc = new XmlDocument();
            xml = XMLSchema.Serialize();

            doc.LoadXml(xml);
            
            XmlElement root = doc.getNamedElement("Root");
            root.SetAttribute("xmlns:etd", "http://google.com");
            root.SetAttribute("xmlns:xsi", "http://google.com");
            root.SetAttribute("xmlns", "http://google.com");
            doc.AppendChild(root);

            doc.Save(path);

Edit. Adding provided sample.

<?xml version="1.0" encoding="UTF-8"?>    <XMLSample xmlns="http://crd.gov.pl/wzor/" xmlns:xsi="http://www.w3.org/2001/" xmlns:etd="http://crd.gov.pl/xml/schematy/">

CodePudding user response：

So to give you an example (based on your sample):

[XmlRoot("XMLSample", Namespace = "http://crd.gov.pl/wzor/")]
public class XmlSample
{
    [XmlElement]
    public string Element1 { get; set; }

    [XmlElement(Namespace = "http://crd.gov.pl/xml/schematy/")]
    public string Element2 { get; set; }
}

Here, the root has the namespace http://crd.gov.pl/wzor/. Element1 inherits that namespace (as none is specified). Element2 has the namespace http://crd.gov.pl/xml/schematy/.

When this is serialised, the serialiser will use the root namespace as the default, so there's no need to explicitly set this. You can set the others to use the prefixes as defined in your sample:

var xsn = new XmlSerializerNamespaces();
xsn.Add("xsi", "http://www.w3.org/2001/");
xsn.Add("etd", "http://crd.gov.pl/xml/schematy/");

You can see this fiddle for a demo, the output is:

<?xml version="1.0" encoding="utf-8"?>
<XMLSample xmlns:xsi="http://www.w3.org/2001/" xmlns:etd="http://crd.gov.pl/xml/schematy/" xmlns="http://crd.gov.pl/wzor/">
  <Element1>foo</Element1>
  <etd:Element2>bar</etd:Element2>
</XMLSample>

Note that Element2 uses the prefix configured for its namespace.