根据2个值使用Linq解析XML

Question

I would like to know how to parse my xml file in c# with LinQ, I made a lot of research but there isn't my precise case..

So here is my xml code :

<WindowsMediaPlayer>
  <Playlist name="playlistdefouf">
    <Element>
        <type>Audio</type>
        <name>lol</name>
    </Element>
        <Element>
        <type>Video</type>
        <name>tamere</name>
    </Element>
  </Playlist>
</WindowsMediaPlayer>

I would like to make a function that verify if a song exists (With type AND name) according to the right playlist too.

For example if I got in parameters playlistname = "playlistdefouf",type = "Audio" and name = "lol" my function will return 1

I already tried to do something but I think I'm lost..

XDocument xmlFile = XDocument.Load(Helper.xmlFolder + "/playlist.xml");
IEnumerable<XElement> elem = xmlFile.Root.Descendants();
IEnumerable<XElement> requete = from d in elem
                    where d.Name == "Playlist"
                    && d.Attribute("name").Value == "playlistdefouf"
                    select d;
IEnumerable<XElement> requete2 = from d in requete.Descendants()
                                where d.Name == "Element"
                                select d;
IEnumerable<XElement> requete3 = from d in requete2.Descendants()
                                    select d;

Answer 1

Here is how to retrieve an IEnumerable of the Playlists that have a specific type and name:

XDocument xmlFile = XDocument.Load("playlists.xml");

var res = from playlist in xmlFile.Root.Elements("Playlist")
    where
        playlist.Attribute("name").Value == "playlistdefouf" &&
        playlist.Element("Element").Element("type").Value == "Audio" &&
        playlist.Element("Element").Element("name").Value == "lol"
    select playlist;

You can get a count of the playlists by using the Count() extension method

res.Count();

Or you can use the Extension method Any() instead of Count to get a boolean that is more expressive if you want to know if a list contains any elements matching your parameters.

Answer 2

This yields the same result but I personally prefer it structured this way:

var xml = XDocument.Load("playlist.xml");
var result =  from playlist in xml.Descendants("Playlist")
              where (string)playlist.Attribute("name") == "playlistdefouf"
              from song in playlist.Descendants("Element")
              where (string)song.Element("type") == "Audio" && (string)song.Element("name") == "lol"
              select playlist;

Then you can use the IEnumerable extensions to get the results you want:

var count = result.Count();
var isExisting = result.Any();
var playlist = result.ToList();