基于条件的LINQ to XML提取

Question

I have the following repetitive XML structure from which I have to create a List of an object:

<entries>
    <entry>
        <start>2013-10-01T00:00:00.000+02:00</start>
        <end>2013-11-01T00:00:00.000+02:00</end>
        <value>27.02</value>
        <isExtracted>true</isExtracted>
    </entry>
    <entry>
        <start>2013-11-01T00:00:00.000+02:00</start>
        <end>2013-12-01T00:00:00.000+02:00</end>
        <value>27.02</value>
        <isExtracted>true</isExtracted>
    </entry>
    <entry>
        <start>2013-12-01T00:00:00.000+02:00</start>
        <end>2014-01-01T00:00:00.000+02:00</end>
        <value>27.02</value>
    </entry>
</entries>

I would like to extract only those elements that has the isExtracted xml tag!

What I do at the moment is the following:

    var extract = xElemMaster.Elements("entries").Elements("entry")
                        .Where(elem => elem.Name.Equals("isExtracted"));

But I'm not getting any results out. What might have probably gone wrong?

Answer 1

You can use Any method

 xElemMaster.Elements("entries")
            .Elements("entry")
            .Where(elem => elem.Elements("isExtracted").Any());

Or just try to get element and check for null:

xElemMaster.Elements("entries")
            .Elements("entry")
            .Where(elem => elem.Element("isExtracted") != null);

To make it more readable I would create an extension method and use it instead:

public static bool HasElement(this XElement source, string elementName)
{
      return source.Element(elementName) != null;
}

xElemMaster.Elements("entries")
            .Elements("entry")
            .Where(elem => elem.Element.HasElement("isExtracted"));

Answer 2

You can search nodes and subnodes with Descendants , then use Any to check if IsExtracted exists.

var extract = xElemMaster.Descendants("entry")   
                .Where(w=>w.Elements("isExtracted").Any())

You might also want to check if isExtracted==True or false

 var extract = x.Descendants("entry")
            .Where(w => w.Elements("isExtracted").Any() && w.Element("isExtracted").Value=="true");