使用Linq到XML时返回分组项目的值

Question

I am trying to use Linq to XML in Visual Studio - C# to pull all of the Elements in an XML file and group them by their value.

This is my XML code:

<?xml version="1.0" encoding="utf-8"?>
 <topTerms>
   <topTerm>Cat</topTerm>
  <topTerm>Dog</topTerm>
  <topTerm>Cat</topTerm>
  <topTerm>Dog</topTerm>
  <topTerm>Cat</topTerm>
  <topTerm>Bird</topTerm>
  <topTerm>Cat</topTerm>
</topTerms>

I am then using the following C# code to try and pull the data and group it by value of the topTerm element.

var top = 0;
        var topName = "";
        var topTermsUrl = Server.MapPath("XML/topTerms.xml");
        XDocument topTermsFile = XDocument.Load(topTermsUrl);
        var topTermDocuments = topTermsFile.Root
                        .Elements("topTerm")
                        .GroupBy(a => a.Value);
    foreach (var topTerm in topTermDocuments)
    {
        topName = topTerm.Value;
        top = topTerm.Count();
    }

However, topTerm.Value is not working. It will count the number of occurrence for each value when I cycle through, but I cannot get the string value being counted. Any ideas?

Answer 1

topTerm is an IGrouping , particularly IGrouping<string, XElement> . So it has a property Key that contains the value by which you grouped:

foreach (var topTerm in topTermDocuments)
{
    topName = topTerm.Key; // Key used here
    top = topTerm.Count();
}

(I assume that in the full code you do more than overwriting variables in a loop).