Question

I have a XDocument where I’d like to sort all of the elements alphabetically. Here’s a simplified version of the structure:

<Config>
 <Server>
    <Id>svr1</Id>
    <Routing>
        <RoutingNodeName>route1</RoutingNodeName>
        <Subscription>
            <Id>1</Id>
        </Subscription>
        <RoutingParameters id="Routing1">
            <Timeout>7200</Timeout>
        </RoutingParameters>
    </Routing>
    <Storage>
            <Physical>HD1</Physical>
    </Storage>
 </Server>
 <Applications>
    <Services>
        <Local></Local>
    </Services>
 </Applications>
</Config>

I’m wanting to sort the elements in this documents at all levels, so far I’m able to sort it like so:

private static XDocument Sort(XDocument file)
{
    return new XDocument(
        new XElement(file.Root.Name,
            from el in file.Root.Elements()
            orderby el.Name.ToString()
            select el));
}

Which produces:

<Config>
<Applications>
  <Services>
    <Local></Local>
  </Services>
</Applications>
<Server>
  <Id>svr1</Id>
  <Routing>
    <RoutingNodeName>route1</RoutingNodeName>
    <Subscription>
      <Id>1</Id>
    </Subscription>
    <RoutingParameters id="Routing1">
      <Timeout>7200</Timeout>
    </RoutingParameters>
  </Routing>
  <Storage>
    <Physical>HD1</Physical>
  </Storage>
</Server>
</Config>

I’d like to be able to sort all of the children elements in the same way (through a recursive function ideally). Any ideas how I can get this going with LINQ?

Thanks for any ideas.

Answer 1

You already have a method to sort the elements. Just apply it recursively:

private static XElement Sort(XElement element)
{
    return new XElement(element.Name,
            from child in element.Elements()
            orderby child.Name.ToString()
            select Sort(child));
}

private static XDocument Sort(XDocument file)
{
    return new XDocument(Sort(file.Root));
}

Note that this strips all non-element nodes (attributes, text, comments, etc.) from your document.

---

If you want to keep the non-element nodes, you have to copy them over:

private static XElement Sort(XElement element)
{
    return new XElement(element.Name,
            element.Attributes(),
            from child in element.Nodes()
            where child.NodeType != XmlNodeType.Element
            select child,
            from child in element.Elements()
            orderby child.Name.ToString()
            select Sort(child));
}

private static XDocument Sort(XDocument file)
{
    return new XDocument(
            file.Declaration,
            from child in file.Nodes()
            where child.NodeType != XmlNodeType.Element
            select child,
            Sort(file.Root));
}