Question

I have an XDocument that contains a number of data items.

I have another XDocument that contains a very small collection of data items. The data items in the smaller document have corresponding elements in the larger document at matching paths.

What I want to do is loop through the smaller document and for each element I find I want to update the larger document so that its corresponding value is replaced with that of the smaller document.

For example, the larger document:

<Rootelement>
  <Desktop>
    <A>
      <El1 label="original blah" />
    </A>
  </Desktop>
  <Desktop>
    <B>
      <El2 />
    </B>
  </Desktop>
  <Desktop>
    <C>
      <El3 label="I'm the label" tooltip="I'm the tooltip" />
    </C>
  </Desktop>
</Rootelement>

The smaller document:

<Rootelement>
  <Desktop>
    <C>
      <El3 label="The NEW Label" tooltip="The NEW Tooltip" />
    </C>
  </Desktop>
</Rootelement>

I want to take the element at the path Rootelement/Desktop/C/El3 and replace the element at the same path in the larger document with the one from the smaller one, so the large document becomes:

<Rootelement>
  <Desktop>
    <A>
      <El1 label="original blah" />
    </A>
  </Desktop>
  <Desktop>
    <B>
      <El2 />
    </B>
  </Desktop>
  <Desktop>
    <C>
      <El3 label="The NEW Label" tooltip="The NEW Tooltip" />
    </C>
  </Desktop>
</Rootelement>

What is the best way for me to do this?

Answer 1

var xDocBig = XDocument.Parse(xmlBig);
var xDocSmall = XDocument.Parse(xmlSmall);

var eBig = xDocBig.XPathSelectElement("/Rootelement/Desktop/C");
var eSmall = xDocSmall.XPathSelectElement("/Rootelement/Desktop/C");

eBig.ReplaceWith(eSmall);

var newXml = xDocBig.ToString();