c# linq to xml to list

Question

I was wondering if there is a way to get a list of results into a list with linq to xml. If I would have the following xml for example:

<?xml version="1.0"?>
<Sports xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <SportPages>
        <SportPage type="test">
            <LinkPage>
                <IDList>
                    <string>1</string>
                    <string>2</string>
                </IDList>
            </LinkPage>
        </SportPage>
    </SportPages>
</Sports>

How could I get a list of strings from the IDList?

I'm fairly new to linq to xml so I just tried some stuff out, I'm currently at this point:

var IDs = from sportpage in xDoc.Descendants("SportPages").Descendants("SportPage")
                      where sportpage.Attribute("type").Value == "Karate"
                      select new
                      {
                          ID = sportpage.Element("LinkPage").Element("IDList").Elements("string")
                      };

But the var is to chaotic to read decently. Isn't there a way I could just get a list of strings from this?

Thanks

marc_s · Accepted Answer · 2010-04-08 14:30:49Z

6

This query works - tested and verified:

var ID2 = (from sportpage in xDoc.Descendants("SportPages").Descendants("SportPage")
           where sportpage.Attribute("type").Value == "Karate"
           select sportpage)
          .Descendants("LinkPage")
          .Descendants("IDList")
          .Elements("string")
          .Select(d => d.Value)
          .ToList();

Gives me a list of two strings, "1" and "2".

answered Apr 8, 2010 at 14:30

marc_s

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2 Comments

Matthew Whited Over a year ago

This will throw a object null exception if you ever have a SportPage element that doesn't have a type attribute.

WtFudgE Over a year ago

solved it, I removed the LinkPage descendants and SportPages descendants because thanks to other replies I figured out it autosearches :) So thanks a lot all of u!

Yuriy Faktorovich · Accepted Answer · 2010-04-08 15:11:47Z

2

var myStrings = xDoc.Descendants("SportPage")
                    .Where(d => d.Attribute("type").Value == "Karate")
                    .Descendants("IDList")
                    .Descendants("string")
                    .Select(d => d.Value);

to see your string:

xDoc.Descendants("SportPage")
    .Descendants("IDList")
    .Where(d => d.Attribute("type").Value == "Karate")
    .Descendants("string")
    .Select(d => d.Value)
    .ToList()
    .ForEach(Console.WriteLine);

edited Apr 8, 2010 at 15:11

answered Apr 8, 2010 at 14:11

Yuriy Faktorovich

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1 Comment

marc_s Over a year ago

but you're neglecting the condition sportpage.Attribute("type").Value == "Karate"

ANeves · Accepted Answer · 2010-04-08 14:15:18Z

1

Do you mean this?

List<string> IDs = xDoc.Descendants("SportPages").Descendants("SportPage")
    .Where( anySportPage => anySportpage.Attribute("type").Value == "Karate" )
    .Select( karateSportPage => karateSportpage.Element("LinkPage").Element("IDList").Elements("string"))
    .ToList();

answered Apr 8, 2010 at 14:15

ANeves

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3 Comments

marc_s Over a year ago

I'm getting: "Error: Cannot implicitly convert type 'System.Collections.Generic.List<System.Collections.Generic.IEnumerable<System.Xml.Linq.XElement>>' to 'System.Collections.Generic.List<string>'"

marc_s Over a year ago

Also you need to be more careful with your upper- and lower-case: e.g. this statement doesn't work: .Where( anySportPage => anySportpage. - you need to use the same casing in both cases!! anySportPage vs. anySportpage - not identical!

ANeves Over a year ago

Born out of not testing and assuming I knew what came out of the .Elements(). (Using var IDs would work, but I never really liked var.) Thanks for the corrections, and for writing down a correct answer. :)

Robin Day · Accepted Answer · 2010-04-08 14:17:15Z

0

I think the reason you find the "var" chaotic is your creation of the anonymous type with the "new" in your select. If you just select the one item you're after then the var will not be an anonymous type.

e.g.

select sportpage.Element("LinkPage").Element("IDList").Elements("string");

However, my preference would be to do that using the . notation like this.

List<string> ids = xDoc.Elements("SportPages").Elements("SportPage").Where(sportPage => sportPage.Attribute("type").Value == "Karate").Elements("LinkPage").Elements("IDList").Elements("string").Select(id => id.Value).ToList();

answered Apr 8, 2010 at 14:17

Robin Day

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Comments

Matthew Whited · Accepted Answer · 2010-04-08 14:31:38Z

0

The biggest issue you were having was that you didn't grab the .Value from the returned element set. But here's another way to do it.

var ids = from sportPage in xDoc.Descendants("SportPage")
          let attrib = sportPage.Attribute("type")
          where attrib != null
          let type = attrib.Value
          where !string.IsNullOrEmpty(type)
              && type == "Karate"
          from id in sportPage.Descendants("IDList").Elements()
          select id.Value;

answered Apr 8, 2010 at 14:31

Matthew Whited

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1 Comment

Matthew Whited Over a year ago

This way is rather lazy. If you have an explicit schema you can use the same thing you have in your example in the question. You just need to add a .Value to the end of the statement in your select.

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