Edit an XML file without rewriting using XmlSerializer in C# - c#

I have an XML file eg:
<?xml version="1.0" encoding="utf-8"?>
<items>
<item>
<id>1</id>
<details></details>
<description></description>
</item>
<item>
<id>2</id>
<details>
</details>
<description></description>
</item>
</items>
Now say suppose I want to modify an XML file such that I want to add some data to details tag for item with id=2. Using XML serializer, I would have to read the whole XML file then select item with item Id 2 and modify that class object and write whole file again? So for every update I would have to read the whole xml file into memory, then edit it in memory and then re-write as a whole to the disk?
Is there any other way to achieve this? Like could I have alogic which would simply update the node to the existing XML file?

Related

How to get nodes where his child node has some value

I have below xml structure:
<?xml version="1.0" encoding="UTF-8" ?>
<rss>
<channel>
<item>
<title>Some Title</title>
</wp:comment>
<wp:comment_approved><![CDATA[1]]></wp:comment_approved>
</wp:comment>
</wp:comment>
<wp:comment_approved><![CDATA[1]]></wp:comment_approved>
</wp:comment>
</item>
</channel>
</rss>
I can easily get all wp:comments by:
xmlNode.SelectNodes("*[name()='wp:comment']")
But how can I get all wp:comments where wp:comment_approved has value 1?
it's updated #Stefan Hegny answer, as you need not comment_approvedelement, but wp:comment
xmlNode.SelectNodes("//*[name()='wp:comment'][./*[local-name() = 'comment_approved' and . = '1']")
i'm not sure if default css locators working here, but in common css xPath i'll use this locator (logic is simple - you seach some element, that contains element with special parameter, so you can adjust this locator to your needs):
//someTag[./innerTag[text() = '1']]

How to use LINQ to get data from an XML file?

I have xml files which look like this:
<?xml version="1.0" encoding="utf-8"?>
<record id="177" restricted="false">
<type>record type</type>
<startdate>2000-10-10</startdate>
<enddate>2014-02-01</enddate>
<titles>
<title xml:lang="en" type="main">Main title</title>
<!-- only one title element with type main -->
<title xml:lang="de" type="official">German title</title>
<!-- can have more titles of type official -->
</titles>
<description>description of the record</description>
<categories>
<category id="122">
<name>category name</name>
<description>category description</description>
</category>
<!-- can have more categories -->
</categories>
<tags>
<tag id="5434">
<name>tag name</name>
<description>tag description</description>
</tag>
<!-- can have more tags -->
</tags>
</record>
How do I select the data from these xml files using LINQ, or should I use something else?
You can load xml into XDocument objects using either the Load() method
for files, or the Parse() method for strings:
var doc = XDocument.Load("your-file.xml");
// OR
var doc = XDocument.Parse(yourXmlString);
Then you can access the data using LINQ:
var titles =
from title in doc.XPathSelectElements("//title")
where title.Attribute("type").Value == "official"
select title.Value;
Was searching for examples of Xmlserializer and found this: How to Deserialize XML document
So why not to try. I did Ctrl+C and Edit -> Paste Special -> Paste XML As Classes in Visual Studio 2013 and... Whoa I got all the classes generated. One condition target framework must be 4.5 and this function is available from Visual Studio 2012+ (as stated in that post)

Reading and Editing XML file

I have an XML file which contains employee details. How can i edit the existing employee names in that MXL file using C# .NET.
Here is the xml file.
<?xml version="1.0" encoding="utf-8"?>
<Employees>
<Employee id="1">
<Name>Employee 1</Name>
<Designation>SE </Designation>
<Qualification>MCA </Qualification>
</Employee>
<Employee id="2">
<Name>Employee 2</Name>
<Designation>SE </Designation>
<Qualification>MCA </Qualification>
</Employee>
<Employee id="3">
<Name>Employee 3</Name>
<Designation>SE </Designation>
<Qualification>MCA </Qualification>
</Employee>
</Employees>
How can i edit the employee names. I am new to xml. For example using Console Application
You can simple do that using Linq to Xml.
using System.Xml.Linq;
...
XDocument xDoc = XDocument.Load(#"Your xml file path goes here"); // or XDocument.Parse("Your xml string goes here");
xDoc.Root.Elements("Employee").First(xe => xe.Attribute("id").Value == "1").Element("Name").Value = "your value";
Here is a good reference for head start: Programming Guide (LINQ to XML)
you can use XML Serialization, in my opinion this is the most comfortable way
of working with c# and xml,
some examples are here:
http://msdn.microsoft.com/en-us/library/58a18dwa(v=vs.110).aspx

How to Split an XML file into multiple XML Files

I am trying to split a XML file to multiple small xml files in C#.net and am
trying to get the best possible approach to this. Any help on this will be
great... Sample example on what I am trying to do...
Source XML document
<?xml version="1.0" standalone="yes"?>
<DATABASE>
<DOC>
<DOCID>8510188</DOCID>
<ISSUE>2010</ISSUE>
<CAT>Literature and Art</CAT>
<TITLE>Test</TITLE>
<TEXT>Test</TEXT>
</DOC>
<DOC>
<DOCID>1510179</DOCID>
<ISSUE>2012</ISSUE>
<CAT>Miscellaneous</CAT>
<TITLE>Test</TITLE>
<TEXT>Test</TEXT>
</DOC>
</DATABASE>
Should split to two xml documents as below
1)
<?xml version="1.0" standalone="yes"?>
<DATABASE>
<DOC>
<DOCID>8510188</DOCID>
<ISSUE>2010</ISSUE>
<CAT>Literature and Art</CAT>
<TITLE>Test</TITLE>
<TEXT>Test</TEXT>
</DOC>
</DATABASE>
2)
<?xml version="1.0" standalone="yes"?>
<DATABASE>
<DOC>
<DOCID>1510179</DOCID>
<ISSUE>2012</ISSUE>
<CAT>Miscellaneous</CAT>
<TITLE>Test</TITLE>
<TEXT>Test</TEXT>
</DOC>
</DATABASE>
Well, I'd use LINQ to XML:
XDocument doc = XDocument.Load("test.xml");
var newDocs = doc.Descendants("DOC")
.Select(d => new XDocument(new XElement("DATABASE", d)));
foreach (var newDoc in newDocs)
{
newDoc.Save(/* work out filename here */);
}
(I'm assuming you want to save them. Maybe you don't need to. I've tested this just by printing them out to the console instead.)

Xml generated with fields & attributes entered by webform

i have the following problem!
I need to generate an Xml Document in asp.net. For this, i need to enter the following information:
- Number of tags.
- Name of each tags (example: , , , etc).
- Attributes of each tag (example: Alex... etc)..
I have already this function that received a List (TAGLIST) with the name of the xml tags.
public void functionxml()
{
string RutaSave = string.Format(#"C:\xml.xml");
var Serializer = new XmlSerializer(typeof(List<string>));
TextWriter textWriter = new StreamWriter(RutaSave);
Serializer.Serialize(textWriter, TagsList);
}
But the xml generated by this function looks like this:
<?xml version="1.0" encoding="utf-8"?>
<dictionary>
<item>
<key>
<string>CAMPO1</string>
</key>
<value>
<anyType xmlns:q1="http://www.w3.org/2001/XMLSchema" d4p1:type="q1:string" xmlns:d4p1="http://www.w3.org/2001/XMLSchema-instance">test</anyType>
</value>
</item>
<item>
<key>
<string>CAMPO2</string>
</key>
<value>
<anyType xmlns:q1="http://www.w3.org/2001/XMLSchema" d4p1:type="q1:int" xmlns:d4p1="http://www.w3.org/2001/XMLSchema-instance">2</anyType>
</value>
</item>
</dictionary>
Please, any help will be welcome!
Thanks in advance.
You should use XMLWriter instead of XMLSerializer. XMLSerializer tries to produce a XML file for an object; some kind of serialization. It is more like a BinarySerializer but it produces XML format instead of byte arrays or streams. XMLWriter is a class which writes a hierarchy into a XML file.

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