Conceptually, the XmlReader provides a forward-only parsing object for the underlying XML files. In other words, you must manage the position in the file logically in your code as the parser can only go forward.
Info XmlReader reduces the memory space required for the parser. It is efficient.
Example. You can use certain methods, such as IsStartElement and the Name property, to detect the location in the file and then execute conditional logic based on this location. This increases complexity.
Property
Create We instantiate an XmlReader instance by assigning an XmlReader reference to the result of the XmlReader.Create static method.
While We see a while-loop construct that evaluates the result of the Read instance method in its expression body.
While
IsStartElement This returns true if the element is not an end tag. It returns true for "<article>" but false for "</article>".
Name The attribute "name" is accessed with the "name" argument in an indexer. This is null when not found.
Indexer
C# program that uses XmlReader type
using System;
using System.Xml;
class Program
{
static void Main()
{
// Create an XML reader for this file.
using (
XmlReader reader = XmlReader.Create(
"perls.xml"))
{
while (reader.Read())
{
// Only detect start elements.
if (reader.IsStartElement())
{
// Get element name and switch on it.
switch (reader.Name)
{
case "perls":
// Detect this element.
Console.WriteLine(
"Start <perls> element.");
break;
case "article":
// Detect this article element.
Console.WriteLine(
"Start <article> element.");
// Search for the attribute name on this current node.
string attribute = reader["name"];
if (attribute != null)
{
Console.WriteLine(
" Has attribute name: " + attribute);
}
// Next read will contain text.
if (reader.Read())
{
Console.WriteLine(
" Text node: " + reader.Value.Trim());
}
break;
}
}
}
}
}
}
<?xml version="1.0" encoding="utf-8" ?>
<perls>
<article name="backgroundworker">
Example text.
</article>
<article name="threadpool">
More text.
</article>
<article></article>
<article>Final text.</article>
</perls>
Start <perls> element.
Start <article> element.
Has attribute name: backgroundworker
Text node: Example text.
Start <article> element.
Has attribute name: threadpool
Text node: More text.
Start <article> element.
Text node:
Start <article> element.
Text node: Final text.
Benefits. Let's review the benefits of XmlReader as opposed to some solutions such as the XElement type. Unfortunately, the XmlReader will introduce more complexity into the parsing code in your program, due to its nature as a forward-only parser.
And XmlReader will not parse an entire file into an object model automatically.
Summary. We looked at a simple example of the XmlReader type in the C# language. This class can be used to implement higher-level parsing code, while retaining top performance and low memory usage.
Thus The XmlReader retains more complexity. With it you can manipulate the XML at a level more suited to many programs.