using XmlReader to get child nodes without knowing their names(in .net)

Question

How do I get the the top level child nodes(unknownA) of root node with XmlReader in .net? Because their names are unknown , ReadToDescendant(string) and ReadToNextSibling(string) won't work.

<root>
    <unknownA/>
    <unknownA/>
    <unknownA>
        <unknownB/>
        <unknownB/>
    </unknownA>
    <unknownA/>
    <unknownA>
        <unknownB/>
        <unknownB>
            <unknownC/>
            <unknownC/>
        </unknownB>
    </unknownA>
    <unknownA/>
</root>

Answer 1

You can walk through the file using XmlReader.Read() , checking the current Depth against the initial depth, until reaching an element end at the initial depth, using the following extension method:

public static class XmlReaderExtensions
{
    public static IEnumerable<string> ReadChildElementNames(this XmlReader xmlReader)
    {
        if (xmlReader == null)
            throw new ArgumentNullException();
        if (xmlReader.NodeType == XmlNodeType.Element && !xmlReader.IsEmptyElement)
        {
            var depth = xmlReader.Depth;
            while (xmlReader.Read())
            {
                if (xmlReader.Depth == depth + 1 && xmlReader.NodeType == XmlNodeType.Element)
                    yield return xmlReader.Name;
                else if (xmlReader.Depth == depth && xmlReader.NodeType == XmlNodeType.EndElement)
                    break;
            }
        }
    }

    public static bool ReadToFirstElement(this XmlReader xmlReader)
    {
        if (xmlReader == null)
            throw new ArgumentNullException();
        while (xmlReader.NodeType != XmlNodeType.Element)
            if (!xmlReader.Read())
                return false;
        return true;
    }
}

Then it could be used as follows:

        var xml = GetXml(); // Your XML string

        using (var textReader = new StringReader(xml))
        using (var xmlReader = XmlReader.Create(textReader))
        {
            xmlReader.ReadToFirstElement();
            var names = xmlReader.ReadChildElementNames().ToArray();
            Console.WriteLine(string.Join("\n", names));
        }