Question

I’m new to C# and XML and trying to develop a small weather plugin for MediaPortal. I’m trying to parse some XML using Linq in Visual C# 2010 Express and have hit a roadblock.

Here is a subset of the XML I am trying to parse:

<forecast>
  <period textForecastName="Monday">Monday</period>
  <textSummary>Sunny. Low 15. High 26.</textSummary>
<temperatures>
  <textSummary>Low 15. High 26.</textSummary>
  <temperature unitType="metric" units="C" class="high">26</temperature>
  <temperature unitType="metric" units="C" class="low">15</temperature>
  </temperatures>
</forecast>

Here is my working code so far:

XDocument loaded = XDocument.Parse(strInputXML);
var forecast = from x in loaded.Descendants("forecast")
select new
{
    textSummary = x.Descendants("textSummary").First().Value,
    Period = x.Descendants("period").First().Value,
    Temperatures = x.Descendants("temperatures"),
    Temperature = x.Descendants("temperature"),
    //code to extract high e.g. High = x.Descendants(...class="high"???),
    //code to extract low  e.g. High = x.Descendants(...class="low"???)
};

My code works up to my placeholder comments, but I can’t figure out how to extract the high (26) and the low (15) from the XML using Linq. I could manually parse it from “Temperature”, but I’m hoping I can learn a bit more about XML structures.

Thanks for any help.
Doug

Answer 1

It looks like you want something like:

High = (int)x.Descendants("temperature")
            .Single(e => (string)e.Attribute("class") == "high")

This finds the only temperature descendant (if there are none or multiple, it will throw) having attribute class with value high, and then casts its value to an integer.

But it isn’t entirely clear.

Can a forecast element have multiple temperatures elements? Can a temperatures element have multiple temperature elements that have class == "high"? How do you want to deal with different unitTypes?

To just get the elements out, you can do something like:

Highs = x.Descendants("temperature")
         .Where(e => (string)e.Attribute("class") == "high")