How to Find XML element by name with XElement in LINQ

There are two main methods you can use for this task:

• XElement.Descendants(name): Recursively searches for all descendants with a specific name.
• XElement.Elements(name): Searches only the immediate child elements for those with the given name. This is useful when you want to limit the search to just one level down.

Both methods return matching elements as an IEnumerable<XElement>. You can then use LINQ methods (or a foreach loop) to manipulate or display these elements.

Finding Elements Using Descendants()

Here’s an example where we use XElement.Descendants() to find all elements named Movie:

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

var xmlString = @"
<Movies>
    <Movie>Shawshank Redemption</Movie>
    <Movie>The Matrix</Movie>
    <Movie>Inception</Movie>
</Movies>";

var moviesXml = XElement.Parse(xmlString);
var movieCount = moviesXml.Descendants("Movie").Count();

Console.WriteLine($"There are {movieCount} movies");

Ouput:

There are 3 movies

Retrieving Element Values

To extract values from the elements, you can use the XElement.Value property, which gives you the content of an element as a string.

Here’s an example where we extract and display the names of all Title elements:

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

var xmlString = @"
<Movies>
    <Movie>
        <Title>Shawshank Redemption</Title>
        <Year>1994</Year>
    </Movie>
    <Movie>
        <Title>The Matrix</Title>
        <Year>1999</Year>
    </Movie>
    <Movie>
        <Title>Inception</Title>
        <Year>2010</Year>
    </Movie>
</Movies>";

var moviesXml = XElement.Parse(xmlString);

foreach (var titleElement in moviesXml.Descendants("Title"))
{
    Console.WriteLine(titleElement.Value);
}

Output:

Shawshank Redemption
The Matrix
Inception

Notice that XElement.Descendants() searches all descendants recursively, so it finds Title elements at any level in the hierarchy.

Modifying Element Values

After finding the elements, you can modify their values in two ways:

1. Change the element’s string value directly using XElement.Value.
2. Use XElement.SetValue() to set a value that is not a string. It will automatically convert the object to a string.

Here’s an example where we change the values of both the Title and Streamable elements for each Movie:

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

var xmlString = @"
<Movies>
    <Movie>
        <Title>Shawshank Redemption</Title>
        <Streamable>false</Streamable>
    </Movie>
    <Movie>
        <Title>The Matrix</Title>
        <Streamable>false</Streamable>
    </Movie>
</Movies>";

var moviesXml = XElement.Parse(xmlString);

foreach (var movie in moviesXml.Descendants("Movie"))
{
    // Change the Title to uppercase
    movie.Element("Title").Value = movie.Element("Title").Value.ToUpper();
    
    // Set Streamable to true
    movie.Element("Streamable").SetValue(true);
}

Console.WriteLine(moviesXml.ToString());

Output:

<Movies>
  <Movie>
    <Title>SHAWSHANK REDEMPTION</Title>
    <Streamable>true</Streamable>
  </Movie>
  <Movie>
    <Title>THE MATRIX</Title>
    <Streamable>true</Streamable>
  </Movie>
</Movies>

In this example, we’ve modified the Title element values by converting them to uppercase and changed the Streamable element value to true.

By using XElement.Descendants() and XElement.Elements(), you can efficiently navigate, search, and modify XML structures in C# with LINQ-to-XML.