Reading data from XML

Question

I m planning to use XML for database purpose  Only thing I was able to do is read whole XML file  I want to be able to read only some data and I don t know how to do that   Here is a simple XML   lt Books gt    lt Book gt     lt Title gt Animals lt  Title gt     lt Author gt J  Anderson lt  Author gt    lt  Book gt    lt Book gt     lt Title gt Car lt  Title gt     lt Author gt L  Sawer lt  Author gt    lt  Book gt   lt  Books gt     I m interested in app where output is gonna be  Books  Animals Cars  Authors  J  Anderson L  Sawer   I m just want to learn how read specific data from XML not whole file     SOLVED  I have used Linq to XML

User · Accepted Answer

I don t think you can  legally  load only part of an XML file  since then it would be malformed  there would be a missing closing element somewhere    Using LINQ-to-XML  you can do var doc   XDocument Load  yourfilepath    From there its just a matter of querying the data you want  say like this   var authors   doc Root Elements   Select  x   gt  x Element  Author        HTH   EDIT   Okay  just to make this a better sample  try this  with  JWL  s suggested improvement    using System  using System Xml Linq   namespace ConsoleApplication1       class Program           static void Main  string   args                  XDocument doc   XDocument Load   XMLFile1 xml                 var authors   doc Descendants   Author                 foreach   var author in authors                     Console WriteLine  author Value                              Console ReadLine                        You will need to adjust the path in XDocument Load   to point to your XML file  but the rest should work  Ask questions about which parts you don t understand

User · Answer

Try GetElementsByTagName method of XMLDocument class to read specific data or LoadXml method to read all data to xml document

User · Answer

Alternatively  you can use XPathNavigator   XmlDocument doc   new XmlDocument    doc LoadXml xml   XPathNavigator navigator   doc CreateNavigator     string books   GetStringValues  Books     navigator     Book Title    string authors   GetStringValues  Authors     navigator     Book Author               lt summary gt      Gets the string values       lt  summary gt       lt param name  description  gt The description  lt  param gt       lt param name  navigator  gt The navigator  lt  param gt       lt param name  xpath  gt The xpath  lt  param gt       lt returns gt  lt  returns gt  private static string GetStringValues string description                                        XPathNavigator navigator  string xpath        StringBuilder sb   new StringBuilder        sb Append description       XPathNodeIterator bookNodesIterator   navigator Select xpath       while  bookNodesIterator MoveNext           sb Append string Format   0     bookNodesIterator Current Value        return sb ToString

User · Answer

as per  Jon Skeet  s comment  you should use a XmlReader only if your file is very big  Here s how to use it  Assuming you have a Book class  public class Book       public string Title  get  set       public string Author  get  set       you can read the XML file line by line with a small memory footprint  like this   public static class XmlHelper       public static IEnumerable lt Book gt  StreamBooks string uri            using  XmlReader reader   XmlReader Create uri                 string title   null              string author   null               reader MoveToContent                while  reader Read                      if  reader NodeType    XmlNodeType Element                      amp  amp  reader Name     Book                         while  reader Read                              if  reader NodeType    XmlNodeType Element  amp  amp                              reader Name     Title                                 title   reader ReadString                                break                                                                      while  reader Read                              if  reader NodeType    XmlNodeType Element  amp  amp                              reader Name     Author                                 author  reader ReadString                                break                                                                      yield return new Book    Title   title  Author   author                                                            Example of usage   string uri     c  test xml      your big XML file  foreach  var book in XmlHelper StreamBooks uri         Console WriteLine  Title  Author   0    1    book Title  book Author

[c#] Reading data from XML

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