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How to use LINQ to XML when XML parent and child nodes have the same name

I am trying to extract some SQL data to XML from a Microsoft Dynamics environment, I am currently using LINQ To XML in C# to read and write to my XML files. One piece of data I need is from a view called SECURITYSUBROLE. Looking at the structure of this view shows that there is a column also named SECURITYSUBROLE. My normal method of extraction has given me this XML.
<SECURITYSUBROLE>
<SECURITYROLE>886301</SECURITYROLE>
<SECURITYSUBROLE>886317</SECURITYSUBROLE>
<VALIDFROM>1900-01-01T00:00:00-06:00</VALIDFROM>
<VALIDFROMTZID>0</VALIDFROMTZID>
<VALIDTO>1900-01-01T00:00:00-06:00</VALIDTO>
<VALIDTOTZID>0</VALIDTOTZID>
<RECVERSION>1</RECVERSION>
<RECID>886317</RECID>
</SECURITYSUBROLE>
When I try to import this data later on, I am getting errors because the parent XML node has the same name as a child node. Here is a snippet of the import method:
XmlReaderSettings settings = new XmlReaderSettings();
settings.CheckCharacters = false;
XmlReader reader = XmlReader.Create(path, settings);
reader.MoveToContent();
int count = 1;
List<XElement> xmlSubset = new List<XElement>();
while (reader.ReadToFollowing(xmlTag))
{
if (count % 1000 == 0)
{
xmlSubset.Add(XElement.Load(reader.ReadSubtree()));
XDocument xmlTemp = new XDocument(new XElement(xmlTag));
foreach (XElement elem in xmlSubset)
{
xmlTemp.Root.Add(elem);
}
xmlSubset = new List<XElement>();
ImportTableByName(connectionString, tableName, xmlTemp);
count = 1;
}
else
{
xmlSubset.Add(XElement.Load(reader.ReadSubtree()));
count++;
}
}
}
It's currently failing on the XmlReader.ReadToFollowing, where it doesn't know where to go next because of the name confusion. So my question has two parts:
1) Is there some better way to be extracting this data other than to XML?
2) Is there a way through LINQ To XML that I can somehow differentiate between the parent and child nodes named exactly the same?

To get the elements (in your case) for SECURITYSUBROLE you can check to see if the element's have children:
XElement root = XElement.Load(path);
var subroles = root.Descendants("SECURITYSUBROLE") // all subroles
.Where(x => !x.HasElements); // only subroles without children

I'm going to suggest a different approach:
1) VS2013 (possibly earlier versions too) has a function to create a class from an XML source. So get one of your XML files and copy the content to your clipboard. Then in a new class file Edit --> Paste Special --> Paste XML as Classes
2) Look into XmlSerialization which will allow you to convert an XML file into an in memory object with a strongly typed class.
XmlSerializer s = new XmlSerializer(yourNewClassTYPE);
TextReader r = new StreamReader(XmlFileLocation);
var dataFromYourXmlAsAStronglyTypedClass = (yourNewlyClassTYPE) s.Deserialize(r);
r.Close();

Query Collection of all XML Elements

I'm looking to parse an XML file, and have the ability to search any element.
My XML code looks rather nontraditional (out of my control):
<DiagReport>
<LicensingData>
<ToolVersion>6.3.9431.0</ToolVersion>
<LicensingStatus>SL_LICENSING</LicensingStatus>
</LicensingData>
<Health>
<Result>PASS</Result>
<TamperedItems></TamperedItems>
</Health>
<Genuine>
<ServerProps>GenuineId</ServerProps>
</Genuine>
</DiagReport>
I'd like to load each singular element into a collection, i.e. one collection including ToolVersion, Result, etc. From there, I'd like to iterate through each element/name pair, and depending upon the element, do something different:
if (element.Equals(Result))
//do something with "PASS"
Is this possible to do with LINQ?

You can use LINQ to XML to iterate through all second level elements:
var xdoc = XDocument.Load(#"C:\test.xml");
foreach (var element in xdoc.Element("DiagReport").Elements().Elements())
{
if (element.Name == "Result")
{
string value = element.Value;
}
}

You can use Linq to Xml to query your Xml document, you can search Elements, Attributes and grab what you need.
More information can be found here: Basic Queries (LINQ to XML)
And you can creat simple querys like below.
XElement root = XElement.Parse(File.ReadAllText("C:\\Test.xml"));
var test = new
{
ToolVersion = root.Descendants("ToolVersion").FirstOrDefault().Value,
Result = root.Descendants("Result").FirstOrDefault().Value
};

Parsing XML file using C#?

I'm new to both XML and C#; I'm trying to find a way to efficiently parse a given xml file to retrieve relevant numerical values, base on the "proj_title" value=heat_run or any other possible values. For example, calculating the duration of a particular test run (proj_end val-proj_start val).
ex.xml:
<proj ID="2">
<proj_title>heat_run</proj_title>
<proj_start>100</proj_start>
<proj_end>200</proj_end>
</proj>
...
We can't search by proj ID since this value is not fixed from test run to test run. The above file is huge: ~8mb, and there's ~2000 tags w/ the name proj_title. is there an efficient way to first find all tag names w/ proj_title="heat_run", then to retrieve the proj start and end value for this particular proj_title using C#??
Here's my current C# code:
public class parser
{
public static void Main()
{
XmlDocument xmlDoc= new XmlDocument();
xmlDoc.Load("ex.xml");
//~2000 tags w/ proj_title
//any more efficient way to just look for proj_title="heat_run" specifically?
XmlNodeList heat_run_nodes=xmlDoc.GetElementsByTagName("proj_title");
}
}

8MB really isn't very large at all by modern standards. Personally I'd use LINQ to XML:
XDocument doc = XDocument.Load("ex.xml");
var projects = doc.Descendants("proj_title")
.Where(x => (string) x == "heat_run")
.Select(x => x.Parent) // Just for simplicity
.Select(x => new {
Start = (int) x.Element("proj_start"),
End = (int) x.Element("proj_end")
});
foreach (var project in projects)
{
Console.WriteLine("Start: {0}; End: {1}", project.Start, project.End);
}
(Obviously adjust this to your own requirements - it's not really clear what you need to do based on the question.)
Alternative query:
var projects = doc.Descendants("proj")
.Where(x => (string) x.Element("proj_title") == "heat_run")
.Select(x => new {
Start = (int) x.Element("proj_start"),
End = (int) x.Element("proj_end")
});

You can use XPath to find all nodes that match, for example:
XmlNodeList matches = xmlDoc.SelectNodes("proj[proj_title='heat_run']")
matches will contain all proj nodes that match the critera. Learn more about XPath: http://www.w3schools.com/xsl/xpath_syntax.asp
MSDN Documentation on SelectNodes

Use XDocument and use the LINQ api.
http://msdn.microsoft.com/en-us/library/bb387098.aspx
If the performance is not what you expect after trying it, you have to look for a sax parser.
A Sax parser will not load the whole document in memory and try to apply an xpath expression on everything in memory. It works more in an event driven approach and in some cases this can be a lot faster and does not use as much memory.
There are probably sax parsers for .NET around there, haven't used them myself for .NET but I did for C++.

Linq To Xml Saving a List Of Nested Objects

I currently load an XML file into a list objects using code like this
XDocument xmlDoc = XDocument.Load(path);
List<ImportDefinition> importDefinitions = xmlDoc.Descendants("Root").Select(xElem => (ImportDefinition)xElem).ToList();
return importDefinitions;
This list of objects contains nested objects and each one has an operator for parsing the XML into the correct form like this
public static explicit operator Rules(XElement xElem)
{
try
{
return new Rules()
{
FileNameRegEx = (string)xElem.Element("FileNameRegEx"),
FileExtension = (string)xElem.Element("FileExtension")
};
}
catch (Exception ex)
{
return null;
}
This works fine for loading the XML. I now want to save this list of objects back to XML after some edits have been made.
I was hoping something like this would work
XElement xml = new XElement("Root",
from p in ObjectList
select new XElement("File",RootObject
));
}
xml.Save("C:\\temp\\newimport.xml");
However this just seems to output this
<?xml version="1.0" encoding="utf-8"?>
<Root>
<File>MyNamespace.RootObject</File>
<File>MyNamespace.RootObject</File>
</Root>
It looks like its not using the custom operators it uses when loading the files to work out the format to save in. Whats the best way to save this data back to XML to the same format it was in when I read it?

Well for one thing you've only shown us the operator for parsing from an XElement... but even so, you're obviously explicitly calling that in your LINQ expression. If you want the equivalent when building XML, you'll need to be explicit there too:
XElement xml = new XElement("Root",
from p in ObjectList
select new XElement("File", (XElement) p));
Personally I'd use methods instead of operators - ToXElement() and FromXElement() - I think it's clearer that way. ToXElement would be an instance method; FromXElement would be a static method. This is a pattern I've used many times, and it's always worked fine.

How to read XML attributes in C#?

I have several XML files that I wish to read attributes from. My main objective is to apply syntax highlighting to rich text box.
For example in one of my XML docs I have: <Keyword name="using">[..] All the files have the same element: Keyword.
So, how can I get the value for the attribute name and put them in a collection of strings for each XML file.
I am using Visual C# 2008.

The other answers will do the job - but the syntax highlighting thingy and the several xml files you say you have makes me thinks you need something faster, why not use a lean and mean XmlReader?
private string[] getNames(string fileName)
{
XmlReader xmlReader = XmlReader.Create(fileName);
List<string> names = new List<string>();
while (xmlReader.Read())
{
//keep reading until we see your element
if (xmlReader.Name.Equals("Keyword") && (xmlReader.NodeType == XmlNodeType.Element))
{
// get attribute from the Xml element here
string name = xmlReader.GetAttribute("name");
// --> now **add to collection** - or whatever
names.Add(name);
}
}
return names.ToArray();
}
Another good option would be the XPathNavigator class - which is faster than XmlDoc and you can use XPath.
Also I would suggest to go with this approach only IFF after you try with the straightforward options you're not happy with performance.

You could use XPath to get all the elements, then a LINQ query to get the values on all the name atttributes you find:
XDocument doc = yourDocument;
var nodes = from element in doc.XPathSelectElements("//Keyword")
let att = element.Attribute("name")
where att != null
select att.Value;
string[] names = nodes.ToArray();
The //Keyword XPath expression means, "all elements in the document, named "Keyword".
Edit: Just saw that you only want elements named Keyword. Updated the code sample.

Like others, I would suggest using LINQ to XML - but I don't think there's much need to use XPath here. Here's a simple method to return all the keyword names within a file:
static IEnumerable<string> GetKeywordNames(string file)
{
return XDocument.Load(file)
.Descendants("Keyword")
.Attributes("name")
.Select(attr => attr.Value);
}
Nice and declarative :)
Note that if you're going to want to use the result more than once, you should call ToList() or ToArray() on it, otherwise it'll reload the file each time. Of course you could change the method to return List<string> or string[] by -adding the relevant call to the end of the chain of method calls, e.g.
static List<string> GetKeywordNames(string file)
{
return XDocument.Load(file)
.Descendants("Keyword")
.Attributes("name")
.Select(attr => attr.Value)
.ToList();
}
Also note that this just gives you the names - I would have expected you to want the other details of the elements, in which case you'd probably want something slightly different. If it turns out you need more, please let us know.

You could use LINQ to XML.
Example:
var xmlFile = XDocument.Load(someFile);
var query = from item in xmlFile.Descendants("childobject")
where !String.IsNullOrEmpty(item.Attribute("using")
select new
{
AttributeValue = item.Attribute("using").Value
};

You'll likely want to use XPath. //Keyword/#name should get you all of the keyword names.
Here's a good introduction: .Net and XML XPath Queries

**<Countries>
<Country name ="ANDORRA">
<state>Andorra (general)</state>
<state>Andorra</state>
</Country>
<Country name ="United Arab Emirates">
<state>Abu Z¸aby</state>
<state>Umm al Qaywayn</state>
</Country>**
public void datass(string file)
{
string file = HttpContext.Current.Server.MapPath("~/App_Data/CS.xml");
XmlDocument doc = new XmlDocument();
if (System.IO.File.Exists(file))
{
//Load the XML File
doc.Load(file);
}
//Get the root element
XmlElement root = doc.DocumentElement;
XmlNodeList subroot = root.SelectNodes("Country");
for (int i = 0; i < subroot.Count; i++)
{
XmlNode elem = subroot.Item(i);
string attrVal = elem.Attributes["name"].Value;
Response.Write(attrVal);
XmlNodeList sub = elem.SelectNodes("state");
for (int j = 0; j < sub.Count; j++)
{
XmlNode elem1 = sub.Item(j);
Response.Write(elem1.InnerText);
}
}
}