Find object in XML file with LINQ

Question

I'm doing a CRUD with students and I'm trying to find a student with LINQ but I don't want to use a list so I want to work directly on the XML file. How can I do that?

My XML file is:

<?xml version="1.0"?>
<ArrayOfStudent xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Student>
      <IDstudent>56</IDstudent>
      <Name>da</Name>
      <Surname>he</Surname>
  </Student>
</ArrayOfStudent>

It works loading my XML into a list and do LINQ but I want to do it in a efficient way.

    public Student FindStudent(string id)
    {
        List<Student> LStudent = GetAll();
        Student student = LStudent.Where(e => e.IDstudent == id).FirstOrDefault();
        return student;

    }

take a look at this [link](https://stackoverflow.com/questions/2470103/best-way-to-manipulate-xml-in-net) — João Paulo Amorim, Feb 21 '19 at 18:45

score 1 · Accepted Answer · answered Feb 21 '19 at 20:32

You can take a look at loading into an xDocument and then using Linq:

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

class Program
{
    public static string FindStudent(XDocument xDoc, string id)
    {
        //this gets the list of Student elements in the document
        var students = xDoc.Elements().First().Elements("Student");

        //this gets the one with the requested id
        //throws an 'InvalidOperationException' if 0 OR more than 1 element found
        var studentById = students.Single(c => c.Element("IDstudent").Value == id);

        //return a string that you already are able to transform into a Student object??
        return studentById.ToString();  
    }

    static void Main(string[] args)
    {
        //Load into an xDocument from file
        XDocument xDoc = XDocument.Load(@"Path\To\Test.xml");

        Console.WriteLine(FindStudent(xDoc, "3"));
        Console.ReadLine();
    }
}

Find object in XML file with LINQ

1 Answers1