I have a big xml file which is composed of multiple xml files. The file structure is like this.
<xml1>
</xml1>
<xml2>
</xml2>
<xml3>
</xml3>
.
.
<xmln>
</xmln>
I want to process each XML file by a LINQ statement but I am not sure how to extract each XML element individually from the file and continue the iteration until the end. I figured experts here would be able to give me the nudge I am looking for. My requirement is to extract the individual elements so i could load into a XDoc element for further processing and continue on through the subsequent elements. Any help on this would be greatly appreciated.
Thanks for reading!!
Assuming each element is a valid XML, you can wrap your document in a top-level tag and then load it just fine:
<wrap>
<xml1>
</xml1>
<xml2>
</xml2>
</wrap>
You can use the System.Xml reference, which includes a lot of built-in functionality, and it allows you to declare an XmlTextReader. More info here.
If this is an error log with individual well formed xml elements, you probably don't want to load it as an XMLDocument. A better option is to use an XPathDocument created with an XmlReader where the XmlReaderSettings specify ConformanceLevel.Fragment. Then you can use an XPathNavigator to access your elements and attributes as needed. See the third answer in this forum post for sample code.
...late by just a year and then some. :)
Related
I have a big xml string that needs to be displayed as a web page. I can achieve this with xslt. Now the users will make changes to certain attributes of the xml displayed on the web page.
When they are done I need to save it back in the same xml format with the modified values.
Please guide me on what would be the best method to handle this.
using asp.net + c#
I've tried something like this in the past, and resorted to using two separate XSLT sheets, one to transform to (X)HTML, and another to transform the edited one back.
Unfortunately there isn't a 'generic' way of doing it, XSLT is a one way transform; e.g. if a stylesheet disregards an element altogether, there's obviously no way of writing an inverse XSLT that will restore it.
Another possibility is to have your XML->HTML stylesheet generate id attributes on input elements in the HTML, and give the value of that attribute a value that can easily be used as a lookup in your source XML. Then you can probably just iterate through each such element in the HTML, and lookup the related element in the source and replace the value. Or the other way round, go through each element in your source, and find the value in the HTML, either works.
Take a look at this utility:
http://www.chilkatsoft.com/refdoc/csHtmlToXmlRef.html
It might be possible to use XSLT to transform it back to HTML too, but without seeing the markup it's tough to tell.
I'm using C# with .net 3.5 and have a few cases where I want to replace some substrings in the XML attributes of an XmlDocument with something else.
One case is to replace the single quote character with ' and the other is to clean up some files that contain valid XML but the attributes' values are no longer appropriate (say replace anything attribute which starts with "myMachine" with "newMachine").
Is there a simple way to do this, or do I need to go through each attribute of every node (recursively)?
One way to approach it is to select a list of the correct elements using Linq to XML, and then iterate over that list. Here's an example one-liner:
XDocument doc = XDocument.Load(path);
doc.XPathSelectElements("//element[#attribute-name = 'myMachine']").ToList().ForEach(x => x.SetAttributeValue("attribute-name", "newMachine"));
You could also do a more traditional iteration.
I suggest taking a look at LINQ to XML. There's a collection of code snippets that can help you get started here - LINQ To XML Tutorials with Examples
LINQ to XML should allow you to do what you're looking to do, and you'll probably find it easy once you've played with it a bit.
How do I use Linq to extract a single XML attribute form each XML file in a directory and put that element in a C# list. Do I have to loop thru each file one-by-one? The XML files are quite large so I'd like to do this without loading the entire file into memory.
Thanks,
j
Unless the files are massive (100 MB+) I would be unable to turn down the elegance of this code:
var result = Directory.GetFiles(filePath)
.Select(path => XDocument.Load(path))
.Select(doc => doc.Root.Element("A").Attribute("B").Value)
.ToList();
I really hope your XML files are not that big though...
You do have to go through every file, and this will mean at least parsing enough of the XML content of each file to get to the required attribute.
XDocument (i.e. LINQ to SQL) will parse and load the complete document in each case, so you might be better using an XmlReader instance directly. This will require more work: you will have to read the XML nodes until you get to the right one, keeping track of where you are.
I'm using C# and i need to create a XML document. Ok, i did, but, in each element i need to put a tc prefix.
The only way that i know, is using xmlDoc.CreateElement("tc", "node1", "file.xsd"), but it is very massive because i have lots of tags and my program its already writted.
Is this the only way?
This might work for you:
XmlReader - I need to edit an element and produce a new one
If you're lucky enough to be using C# 3.5, take a look at LINQ to XML.
Here's a document on How to: Create a Document with Namespaces (C#) (LINQ to XML) from MSDN for the LINQ to XML API.
And if you've never seen LINQ to XML before, take a look at this 5 minute overview
I have a similar question like XML indenting when injecting an XML string into an XmlWriter.
I also use XmlWriter.WriteRaw to output an XML fragment into an xml node. This document fragment does not follow the idention which would be nice. The answer given on the post above does not work for XML fragments. Well, I can read the fragment with the XmlReader, but WriteNode does not work with document fragments (see http://msdn.microsoft.com/en-us/library/1wd6aw1b.aspx).
Any hints on how to cheat to get proper indentation?
Thanks for any hints
It's an old question, but I got the same problem today. My solution is to use XmlDocument.WriteContentTo method:
var innerXmlDoc = new XmlDocument();
innerXmlDoc.LoadXml("<params><param id=\"param1\" value=\"value1\"/></params>");
innerXmlDoc.WriteContentTo(xmlWriter);
https://dotnetfiddle.net/a2928r
You could build a valid Xml-Document in memory containing your xml fragment. Then read this document with the XmlReader (e.g. by using MemoryStream) and let the XmlWriter write indented xml.
A faster approach wold be indenting the xml yourself by manipulating the string. Search for <, increase the nesting level and add the indention spaces. If you find </ or a self closing tag decrease the nesting level and append a \n
I don't think there is a fast and nice solution to your problem, but i might be wrong...