Question

Three part question.

Is it possible to locate a specific XML node by a child inside of it to retrieve other children of the parent? Example:

<House>
    <Kitchen>
        <Appliance>
            <Name>Refrigerator</Name>
            <Brand>Maytag</Brand>
            <Model>F2039-39</Model>
        </Appliance>
        <Appliance>
            <Name>Toaster</Name>
            <Brand>Black and Decker</Brand>
            <Model>B8d-k30</Model>
        </Appliance>
    </Kitchen>
</House>

So for this, I would like to locate the appropriate Appliance node by searching for “Refrigerator” or “Toaster”, and retrieve the brand from it.

The second part of this question is this: Is this a stupid way to do it? Would using an attribute in the Appliance tag make this a lot easier? If so, how would I locate it that way?

As for the third part, once I locate the Appliance, how would I go about changing say, the Model, of that particular appliance?

Answer 1

Using XLinq, you can perform this query fairly naturally:

// Given:
//   var xdoc = XDocument.Load(...);
//   string applianceName = "Toaster";

// Find the appliance node who has a sub-element <Name> matching the appliance
var app = xdoc.Root
              .Descendants("Appliance")
              .SingleOrDefault(e => (string)e.Element("Name") == applianceName);

// If we've found one and it matches, make a change
if (app != null)
{
    if (((string)app.Element("Model")).StartsWith("B8d-k30"))
    {
        app.Element("Model").Value = "B8d-k30 Mark II";
    }
}

xdoc.Save(@"output.xml"); // save changes back to the document