How to query a peer XMLNode .NET

I h开发者_JAVA技巧ave an xml file. I want to query a peer node in C#.

For ex: For a given input xml file as below, i want to query the title using the artist as an input. How do i do this ?? i.e Input --> Pink Floyd, Output -----> Division Bell ..

<catalog>
 <cd>
      <title>Division Bell<title>
      <artist>Pink Floyd<artist>
      <price>29$<price>
 </cd>

 <cd>
      <title>Relapse<title>
      <artist>Eminem<artist>
      <price>19$<price>
 </cd>

</catalog>

---

You could use a XDocument:

using System;
using System.Linq;
using System.Xml.Linq;

class Program
{
    static void Main()
    {
        var doc = XDocument.Load("test.xml");

        var result = 
            (from cd in doc.Root.Descendants("cd")
             let artist = cd.Element("artist")
             let title = cd.Element("title")
             where artist != null && title != null && artist.Value == "Pink Floyd"
             select title.Value
            ).FirstOrDefault();
        Console.WriteLine(result);
    }
}

---

Its quite easy tor read xml in .net

XDocument loaded = XDocument.Load(@"C:\youxml.xml");


 var query = from xElem in loaded.Descendants("cd")
           where xElem.Element("artist").Value == "Eminem"
                    select new Friend
                    {
                        Title = xElem.Attribute("title").Value
                    }; 

Make use of Linq To XML or XLINQ will resolve you issue easily.

Also check this : http://msdn.microsoft.com/en-us/library/bb308960.aspx

---

You can also use XPath syntax.

here is an example:

string inputArtist = "Pink Floyd";
var doc = XDocument.Load("test.xml");
XmlNode cdTitleNode = doc.SelectSingleNode("//cd[artist='" + inputArtist + "']/title");

string outputTitle = cdTitleNode.InnerText;

There is an excellent XPATH simulator on http://www.whitebeam.org/library/guide/TechNotes/xpathtestbed.rhtm to try you Xpath expressions.

You can also found a good tutorial there, but a fast search on the web will result in many web pages explaining all about XPath usage and syntax.

---

Using XPath, you can return a match:

using System.Xml;
using System.Xml.XPath;

public string QuerySearch(string file, string artist) {

   // create an XML Document and load the file
   XmlDocument xd = new XmlDocument();
   xd.Load(file);

   // get the root xml element
   XmlElement root = xd.DocumentElement;

   // get the list of artists
   XmlNodeList aristList = root.GetElementsByTagName("artist");

   // get the list of titles's
   XmlNodeList titleList = root.GetElementsByTagName("title");

   // find match
   for (int i = 0;i < aristList.Count; i++) {
      if (aristList.Item(i).InnerText == artist) {
        return titleList.Item(i).InnerText
      } 
   }
return "no match found.";
}