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Is there a simple method of parsing XML files in C#? If so, what?
It's very simple. I know these are standard methods, but you can create your own library to deal with that much better.
Here are some examples:
XmlDocument xmlDoc= new XmlDocument(); // Create an XML document object
xmlDoc.Load("yourXMLFile.xml"); // Load the XML document from the specified file
// Get elements
XmlNodeList girlAddress = xmlDoc.GetElementsByTagName("gAddress");
XmlNodeList girlAge = xmlDoc.GetElementsByTagName("gAge");
XmlNodeList girlCellPhoneNumber = xmlDoc.GetElementsByTagName("gPhone");
// Display the results
Console.WriteLine("Address: " + girlAddress[0].InnerText);
Console.WriteLine("Age: " + girlAge[0].InnerText);
Console.WriteLine("Phone Number: " + girlCellPhoneNumber[0].InnerText);
Also, there are some other methods to work with. For example, here. And I think there is no one best method to do this; you always need to choose it by yourself, what is most suitable for you.
I'd use LINQ to XML if you're in .NET 3.5 or higher.
Use a good XSD Schema to create a set of classes with xsd.exe and use an XmlSerializer to create a object tree out of your XML and vice versa. If you have few restrictions on your model, you could even try to create a direct mapping between you model classes and the XML with the Xml*Attributes.
There is an introductory article about XML Serialisation on MSDN.
Performance tip: Constructing an XmlSerializer is expensive. Keep a reference to your XmlSerializer instance if you intend to parse/write multiple XML files.
If you're processing a large amount of data (many megabytes) then you want to be using XmlReader to stream parse the XML.
Anything else (XPathNavigator, XElement, XmlDocument and even XmlSerializer if you keep the full generated object graph) will result in high memory usage and also a very slow load time.
Of course, if you need all the data in memory anyway, then you may not have much choice.
Use XmlTextReader, XmlReader, XmlNodeReader and the System.Xml.XPath namespace. And (XPathNavigator, XPathDocument, XPathExpression, XPathnodeIterator).
Usually XPath makes reading XML easier, which is what you might be looking for.
I have just recently been required to work on an application which involved the parsing of an XML document and I agree with Jon Galloway that the LINQ to XML based approach is, in my opinion, the best. I did however have to dig a little to find usable examples, so without further ado, here are a few!
Any comments welcome as this code works but may not be perfect and I would like to learn more about parsing XML for this project!
public void ParseXML(string filePath)
{
// create document instance using XML file path
XDocument doc = XDocument.Load(filePath);
// get the namespace to that within of the XML (xmlns="...")
XElement root = doc.Root;
XNamespace ns = root.GetDefaultNamespace();
// obtain a list of elements with specific tag
IEnumerable<XElement> elements = from c in doc.Descendants(ns + "exampleTagName") select c;
// obtain a single element with specific tag (first instance), useful if only expecting one instance of the tag in the target doc
XElement element = (from c in doc.Descendants(ns + "exampleTagName" select c).First();
// obtain an element from within an element, same as from doc
XElement embeddedElement = (from c in element.Descendants(ns + "exampleEmbeddedTagName" select c).First();
// obtain an attribute from an element
XAttribute attribute = element.Attribute("exampleAttributeName");
}
With these functions I was able to parse any element and any attribute from an XML file no problem at all!
In Addition you can use XPath selector in the following way (easy way to select specific nodes):
XmlDocument doc = new XmlDocument();
doc.Load("test.xml");
var found = doc.DocumentElement.SelectNodes("//book[#title='Barry Poter']"); // select all Book elements in whole dom, with attribute title with value 'Barry Poter'
// Retrieve your data here or change XML here:
foreach (XmlNode book in nodeList)
{
book.InnerText="The story began as it was...";
}
Console.WriteLine("Display XML:");
doc.Save(Console.Out);
the documentation
If you're using .NET 2.0, try XmlReader and its subclasses XmlTextReader, and XmlValidatingReader. They provide a fast, lightweight (memory usage, etc.), forward-only way to parse an XML file.
If you need XPath capabilities, try the XPathNavigator. If you need the entire document in memory try XmlDocument.
I'm not sure whether "best practice for parsing XML" exists. There are numerous technologies suited for different situations. Which way to use depends on the concrete scenario.
You can go with LINQ to XML, XmlReader, XPathNavigator or even regular expressions. If you elaborate your needs, I can try to give some suggestions.
You can parse the XML using this library System.Xml.Linq. Below is the sample code I used to parse a XML file
public CatSubCatList GenerateCategoryListFromProductFeedXML()
{
string path = System.Web.HttpContext.Current.Server.MapPath(_xmlFilePath);
XDocument xDoc = XDocument.Load(path);
XElement xElement = XElement.Parse(xDoc.ToString());
List<Category> lstCategory = xElement.Elements("Product").Select(d => new Category
{
Code = Convert.ToString(d.Element("CategoryCode").Value),
CategoryPath = d.Element("CategoryPath").Value,
Name = GetCateOrSubCategory(d.Element("CategoryPath").Value, 0), // Category
SubCategoryName = GetCateOrSubCategory(d.Element("CategoryPath").Value, 1) // Sub Category
}).GroupBy(x => new { x.Code, x.SubCategoryName }).Select(x => x.First()).ToList();
CatSubCatList catSubCatList = GetFinalCategoryListFromXML(lstCategory);
return catSubCatList;
}
You can use ExtendedXmlSerializer to serialize and deserialize.
Instalation
You can install ExtendedXmlSerializer from nuget or run the following command:
Install-Package ExtendedXmlSerializer
Serialization:
ExtendedXmlSerializer serializer = new ExtendedXmlSerializer();
var obj = new Message();
var xml = serializer.Serialize(obj);
Deserialization
var obj2 = serializer.Deserialize<Message>(xml);
Standard XML Serializer in .NET is very limited.
Does not support serialization of class with circular reference or class with interface property,
Does not support Dictionaries,
There is no mechanism for reading the old version of XML,
If you want create custom serializer, your class must inherit from IXmlSerializable. This means that your class will not be a POCO class,
Does not support IoC.
ExtendedXmlSerializer can do this and much more.
ExtendedXmlSerializer support .NET 4.5 or higher and .NET Core. You can integrate it with WebApi and AspCore.
You can use XmlDocument and for manipulating or retrieve data from attributes you can Linq to XML classes.
Assume this simple XML fragment in which there may or may not be the xml declaration and has exactly one NodeElement as a root node, followed by exactly one other NodeElement, which may contain an assortment of various number of different kinds of elements.
<?xml version="1.0">
<NodeElement xmlns="xyz">
<NodeElement xmlns="">
<SomeElement></SomeElement>
</NodeElement>
</NodeElement>
How could I go about selecting the inner NodeElement and its contents without the namespace? For instance, "//*[local-name()='NodeElement/NodeElement[1]']" (and other variations I've tried) doesn't seem to yield results.
As for in general the thing that I'm really trying to accomplish is to Deserialize a fragment of a larger XML document contained in a XmlDocument. Something like the following
var doc = new XmlDocument();
doc.LoadXml(File.ReadAllText(#"trickynodefile.xml")); //ReadAllText to avoid Unicode trouble.
var n = doc.SelectSingleNode("//*[local-name()='NodeElement/NodeElement[1]']");
using(var reader = XmlReader.Create(new StringReader(n.OuterXml)))
{
var obj = new XmlSerializer(typeof(NodeElementNodeElement)).Deserialize(reader);
I believe I'm missing just the right XPath expression, which seem to be rather elusive. Any help much appreciated!
Try this:
/*/*
It selects children of the root node.
Or
/*/*[local-name() = 'NodeElement']
It selects children with local-name() = 'NodeElement' of the root node.
Anyway in your case both expressions select <NodeElement xmlns="">.
walk the tree
foreach(XmlNode node in doc.DocumentElement.childnodes[0].childnodes)
{
// do something with node
}
hideously fragile of course might want to check for nulls here and there.
I've found a lot of articles about how to get node content by using simple XPath expression and C#, for example:
XPath:
/bookstore/author/first-name
C#:
string xpathExpression = "/bookstore/author/first-name";
nodes = navigator.Select(xpathExpression);
I wonder how to get content that is inside of an element, and the same element is inside another element and another and another.
Just take a look on below code:
<Cell>
<CellContent>
<Para>
<ParaLine>
<String>ABCabcABC abcABC abc ABCABCABC.</string>
</ParaLine>
</Para>
</CellContent>
</Cell>
I only want to extract content ABCabcABC abcABC abc ABCABCABC. from String element.
Do you know how to resolve problem by use XPath expression and .Net C#?
After googling c# .net xpath for few seconds you'll find this article, which provides example which you can easily modify to use XPathDocument, XPathNavigator and XPathNavigator::SelectSingleNode():
XPathNavigator nav;
XPathDocument docNav;
string xPath;
docNav = new XPathDocument("c:\\books.xml");
nav = docNav.CreateNavigator();
xPath = "/Cell/CellContent/Para/ParaLine/String/text()";
string value = nav.SelectSingleNode(xPath).Value
I recommend more reading on xPath syntax. Much more.
navigator.SelectSingleNode("/Cell/CellContent/Para/ParaLine/String/text()").Value
You can use Linq to XML as well to get value of specified element
var list = XDocument.Parse("xml string").Descendants("ParaLine")
.Select(x => x.Element("string").Value).ToList();
From above query you will get value of all the string element which are inside ParaLine tag.
I am using c# console app to get xml document. Now once xmldocument is loaded i want to search for specific href tag:
href="/abc/def
inside the xml document.
once that node is found i want to strip tag completly and just show Hello.
Hello
I think i can simply get the tag using regex. But can anyone please tell me how can i remove the href tag completly using regex?
xml & html same difference: tagged content. xml is stricter in it's formatting.
for this use case I would use transformations and xpath queries rebuild the document. As #Yahia stated, regex on tagged documents is typically a bad idea. the regex for parsing is far to complex to be affective as a generic solution.
The most popular technology for similar tasks is called XPath. (It is also a key component of XQuery and XSLT.) Would the following perhaps solve your task, too?
root.SelectSingleNode("//a[#href='/abc/def']").InnerText = "Hello";
You could try
string x = #"<?xml version='1.0'?>
<EXAMPLE>
<a href='/abc/def'>Hello</a>
</EXAMPLE>";
System.Xml.XmlDocument doc = new XmlDocument();
doc.LoadXml(x);
XmlNode n = doc.SelectSingleNode("//a[#href='/abc/def']");
XmlNode p = n.ParentNode;
p.RemoveChild(n);
System.Xml.XmlNode newNode = doc.CreateNode("element", "a", "");
newNode.InnerXml = "Hello";
p.AppendChild(newNode);
Not really sure if this is what you are trying to do but it should be enough to get you headed in right direction.
I have an xml string that I wish to traverse using LINQ to XML (I have never used this, so wish to learn). However when I try to use
XDocument xDoc = XDocument.Load(adminUsersXML);
var users = from result in xDoc.Descendants("Result")
select new
{
test = result.Element("USER_ID").Value
};
I get an error message saying illegal characters in path. reading up on it, it's because I cannot pass a standard string in this way. Is there a way to use XML LINQ qith a standard string?
Thanks.
My guess is that adminUsersXML is the XML itself rather than a path to a file containing XML. If that's the case, just use:
XDocument doc = XDocument.Parse(adminUsersXML);
As said in MSDN, you must use the Parse function to create a XDocument from a string.
I think adminUserXML is not a file but a string containing xml, which should be parsed to convert to XDocument with XDocument.Parse(adminUserXML)