How to remove all namespaces from XML with C#?

Question

I am looking for the clean, elegant and smart solution to remove namespacees from all XML elements? How would function to do that look like?

Defined interface:

Answer 1

I know this question is supposedly solved, but I wasn't totally happy with the way it was implemented. I found another source over here on the MSDN blogs that has an overridden XmlTextWriter class that strips out the namespaces. I tweaked it a bit to get some other things I wanted in such as pretty formatting and preserving the root element. Here is what I have in my project at the moment.

http://blogs.msdn.com/b/kaevans/archive/2004/08/02/206432.aspx

Class

/// 

/// Modified XML writer that writes (almost) no namespaces out with pretty formatting
/// 
/// 
public class XmlNoNamespaceWriter : XmlTextWriter
{
    private bool _SkipAttribute = false;
    private int _EncounteredNamespaceCount = 0;

    public XmlNoNamespaceWriter(TextWriter writer)
        : base(writer)
    {
        this.Formatting = System.Xml.Formatting.Indented;
    }

    public override void WriteStartElement(string prefix, string localName, string ns)
    {
        base.WriteStartElement(null, localName, null);
    }

    public override void WriteStartAttribute(string prefix, string localName, string ns)
    {
        //If the prefix or localname are "xmlns", don't write it.
        //HOWEVER... if the 1st element (root?) has a namespace we will write it.
        if ((prefix.CompareTo("xmlns") == 0
                || localName.CompareTo("xmlns") == 0)
            && _EncounteredNamespaceCount++ > 0)
        {
            _SkipAttribute = true;
        }
        else
        {
            base.WriteStartAttribute(null, localName, null);
        }
    }

    public override void WriteString(string text)
    {
        //If we are writing an attribute, the text for the xmlns
        //or xmlns:prefix declaration would occur here.  Skip
        //it if this is the case.
        if (!_SkipAttribute)
        {
            base.WriteString(text);
        }
    }

    public override void WriteEndAttribute()
    {
        //If we skipped the WriteStartAttribute call, we have to
        //skip the WriteEndAttribute call as well or else the XmlWriter
        //will have an invalid state.
        if (!_SkipAttribute)
        {
            base.WriteEndAttribute();
        }
        //reset the boolean for the next attribute.
        _SkipAttribute = false;
    }

    public override void WriteQualifiedName(string localName, string ns)
    {
        //Always write the qualified name using only the
        //localname.
        base.WriteQualifiedName(localName, null);
    }
}

Usage

//Save the updated document using our modified (almost) no-namespace XML writer
using(StreamWriter sw = new StreamWriter(this.XmlDocumentPath))
using(XmlNoNamespaceWriter xw = new XmlNoNamespaceWriter(sw))
{
    //This variable is of type `XmlDocument`
    this.XmlDocumentRoot.Save(xw);
}