Question

I have an XML doc. For example this:

<Root xmlns:x="anynamespace" xmlns:html="htmlnamespace">
   <x:Data>bla bla</x:Data>
</Root>

Here I got html namespace to format data. BUT value of element can be e.g.
<html:Font ...>bla bla</html:Font> or
bla <html:Font ...>bla</htmk:Font>

In my C# code I do this:
new XElement(main + "Data",myvalue); //main is namespace
As a result I got <x:Data>&lt;html:Font ...&gt;bla bla etc. Linq replaced key tags with their text codes. So this is unacceptable.

Then i tried this:new XElement(main + "Data",XElement.Parse(myvalue));
There I got exception that prefix html didnt recognized.

Does anyone faced such problem? How did you solve that?

Answer 1

Usually you would not construct the contents from a string but rather simply construct the nodes using LINQ to XML e.g.

            XElement foo = XElement.Parse(@"<foo xmlns=""http://example.com/ns1"" xmlns:html=""http://example.com/html"">
  <bar>bar 1</bar>
</foo>");
            foo.Add(new XElement(foo.GetNamespaceOfPrefix("html") + "p", "Test"));

            Console.WriteLine(foo);

creates the XML

<foo xmlns="http://example.com/ns1" xmlns:html="http://example.com/html">
  <bar>bar 1</bar>
  <html:p>Test</html:p>
</foo>

If you want to parse a fragment given as a string then perhaps the following approach helps:

        public static void AddWithContext(this XElement element, string fragment)
        {
            XmlNameTable nt = new NameTable();
            XmlNamespaceManager mgr = new XmlNamespaceManager(nt);

            IDictionary<string, string> inScopeNamespaces = element.CreateNavigator().GetNamespacesInScope(XmlNamespaceScope.ExcludeXml);

            foreach (string prefix in inScopeNamespaces.Keys)
            {
                mgr.AddNamespace(prefix, inScopeNamespaces[prefix]);
            }

            using (XmlWriter xw = element.CreateWriter())
            {
                using (StringReader sr = new StringReader(fragment))
                {
                    using (XmlReader xr = XmlReader.Create(sr, new XmlReaderSettings() { ConformanceLevel = ConformanceLevel.Fragment }, new XmlParserContext(nt, mgr, xw.XmlLang, xw.XmlSpace)))
                    {
                        xw.WriteNode(xr, false);
                    }
                }
                xw.Close();
            }
        }
    }

    class Program
    {
        static void Main()
        {
            XElement foo = XElement.Parse(@"<foo xmlns=""http://example.com/ns1"" xmlns:html=""http://example.com/html"">
  <bar>bar 1</bar>
</foo>");
            foo.Add(new XElement(foo.GetNamespaceOfPrefix("html") + "p", "Test"));

            Console.WriteLine(foo);
            Console.WriteLine();

            foo.AddWithContext("<html:p>Test 2.</html:p><bar>bar 2</bar><html:b>Test 3.</html:b>");

            foo.Save(Console.Out, SaveOptions.OmitDuplicateNamespaces);

        }

That way I get

<foo xmlns="http://example.com/ns1" xmlns:html="http://example.com/html">
  <bar>bar 1</bar>
  <html:p>Test</html:p>
  <html:p>Test 2.</html:p>
  <bar>bar 2</bar>
  <html:b>Test 3.</html:b>
</foo>