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Searching Xml Document with linq doesn't return anything

I'm trying to learn how to save and extract data with XML in C#, and even though I've read various answers to similar questions on here, I cannot get a hold of why my statement isn't returning anything.
The program I'm writing is just a test, in which I've saved data about a couple movies in the xml document and now I'm trying to retrieve some of them based on their cost.
This is the class that I've written for searching:
class ExtractData
{
private XDocument _xdoc;
public List<string> SearchByCost(double cost)
{
_xdoc = XDocument.Load(FileLocation.XmlFileLocation);
List<string> list = new List<string>();
var movies = from movie in _xdoc.Root.Elements("Name")
where Convert.ToDouble(movie.Element("Cost").Value) < cost
select movie;
foreach (var item in movies)
{
list.Add(item.Value);
}
return list;
}
}
This is how I'm trying to make it print it in the console:
eData = new ExtractData();
foreach (var movie in eData.SearchByCost(9))
{
Console.WriteLine(movie);
}
And this is the content of the XML document:
<?xml version="1.0" encoding="utf-8"?>
<Movies>
<Movie>
<Id>1</Id>
<Name>Shawshank Redemption</Name>
<Director>Frank Darabont</Director>
<Year>1994</Year>
<Cost>9.95</Cost>
</Movie>
<Movie>
<Id>2</Id>
<Name>Pulp Fiction</Name>
<Director>Quentin Tarantino</Director>
<Year>1995</Year>
<Cost>8.95</Cost>
</Movie>
<Movie>
<Id>3</Id>
<Name>Sharknado</Name>
<Director>Anthony Ferrante</Director>
<Year>2013</Year>
<Cost>5.95</Cost>
</Movie>
</Movies>
I hope this is enough information to try and help me out, and thanks in advance! :)

Root element contains Movie elements:
var movies = from movie in _xdoc.Root.Elements("Movie") // here instead of "Name"
where (double)movie.Element("Cost") < cost
select movie;
Also, XElement supports explicit casting to double. And you can replace the second loop with LINQ query (assume you want to select names of movies):
List<string> list = movies.Select(m => (string)m.Element("Name")).ToList();

In plain English, you seem to be trying to find movies cheaper than 9 (of some arbitrary currency).
You can write this as:
public IReadOnlyCollection<string> SearchByCost(XDocument xdoc, double cost)
{
return xdoc.Root.Elements("Movie")
.Where(movie => (double)movie.Element("Cost") < cost)
.Select(movie => movie.Element("Name").Value)
.ToList();
}

delete a node from sitemap xml

I have sitemap format as below.
I want to delete a complete node that
I find loc.
For example:
Where a node has <loc>with a value of http://www.my.com/en/flight1.
I want to delete the <url> node and his child
I want to delete loc
than lastmod than priority and than changefreq
<url>
<loc>http://www.my.com/en/flight1
</loc>
<lastmod>2015-03-05</lastmod>
<priority>0.5</priority>
<changefreq>never</changefreq>
</url>
<url>
<loc>
http://www.my.com/en/flight2
</loc>
<lastmod>2015-03-05</lastmod>
<priority>0.5</priority>
<changefreq>never</changefreq>
</url>
<url>
<loc>
http://www.my.com/en/flight3
</loc>
<lastmod>2015-03-05</lastmod>
<priority>0.5</priority>
<changefreq>never</changefreq>
</url>

If you're using C# you should use System.xml.linq (XDocument)
You can remove a node like so:
XDocument.Load(/*URI*/);
var elements = document.Root.Elements().Where(e => e.Element("loc") != null && e.Element("loc").Value == "http://www.my.com/en/flight1");
foreach (var url in elements)
{
url.Remove();
}

Check for missing int value xml element

In my C# program, I'm loading car data from an xml file into car objects.
This is my xml file:
<Car>
<CarID>1</CarID>
<CarName>Honda</CarName>
<CarColor>Blue</CarColor>
</Car>
<Car>
<CarName>Ford</CarName>
<CarColor>Yellow</CarColor>
</Car>
<Car>
<CarID>3</CarID>
<CarName>BMW</CarName>
<CarColor>Green</CarColor>
</Car>
NOTE THAT the second car entry does NOT have an ID. So I would need to check for this to avoid a null exception.
I load the xml data in my C# code like this:
List<Car> Cars =
(
from el in XDocument.Load("XML_Files/cars.xml").Root.Elements("Car")
select new Car
{
CarID = (int)el.Element("CarID"),
CarName = (string)el.Element("CarName"),
CarColor = (string)el.Element("CarColor")
}).ToList();
I've read in another question that to get around this, for string data, we replace this:
CarName = (string)el.Element("CarName")
with this:
CarName = ((string)el.Element("CarName") != null) ? (string)el.Element("CarName") : string.Empty
That works fine for string values, but what I cannot figure out is how to apply this logic for int values.
So how do I modify this line:
CarID = (int)el.Element("CarID")
To test for the null value?
I've tried this way, but it does not work:
CarID = ((int)el.Element("CarID") >= 0) ? Convert.ToInt32(el.Element("CarID").Value) : 0
Any suggestions?

You're doing two fundamentally different checks in your two examples. In the string example, you're checking if the element is null. In the int example, you're assuming that it exists and jump straight to checking the integer value. Check first that it's not null like you do with the string example.
CarID = (el.Element("CarID") != null) ? Convert.ToInt32(el.Element("CarID").Value) : 0;

C# Linq to XML query

<World>
<Animals>
<Tab>
<Dogs id ="1">
<Dog1></Dog1>
<Dog2></Dog2>
<Dog3></Dog3>
</Dogs>
<Dogs id ="2"></Dogs>
<Dogs id ="3"></Dogs>
</Tab>
</Animals>
</World>
How do I get all elements under tag where id == 1?
My Linq query. (doesn't work) why?
XDocument xml= XDocument.Load(xml.xml);
var elements = from e in xml.Descendants("Animals").Descendants("Tab").Elements("Dogs")
where e.Attribute("id").toString().Equals("1")
select c;
Could you check it please?
Thanks!

var result = xdoc.Descendants("World")
.Descendants("Animals")
.Descendants("Tab")
.Elements("Dogs")
.Where(n => n.Attribute("id").Value == "1");
Output:
<Dogs id="1">
<Dog1></Dog1>
<Dog2></Dog2>
<Dog3></Dog3>
</Dogs>

Or use XPath:
xml.XPathSelectElements("/World/Animals/Tab/Dogs[#id=1]")
or
xml.XPathSelectElements("//Dogs[#id=1]")
which would find all Dogs wherever they occurred.

From your sample data I think you want
//from e in xml.Descendants("Animals").Descendants("Tab").Elements("Dogs")
from e in xml.Descendants("Animals").Elements("Tab").Descendants("Dogs")
And in the same line, Descendants("Animals") could be Elements("Animals") if you want to enforce the structure.
For the rest your query looks OK.

Select unique XElements (by attribute) with a filter using LinqToXml

I have an XML document looking similar to this:
<items>
<item cat="1" owner="14">bla</item>
<item cat="1" owner="9">bla</item>
<item cat="1" owner="14">bla</item>
<item cat="2" owner="12">bla</item>
<item cat="2" owner="12">bla</item>
</items>
Now I'd like to get all unique owners (I actually only need the attribute value of the owner) belonging to a specified category using a linq query. In my example, the query for cat 1 would return a list containing 9 and 14. How can I do that? Linq syntax would be preferred over Lambdas. Thanks in advance ;)

Presuming the fragment is in itemsElement:
var distinctOwners = (from item in itemsElement.Element("item")
where itemElements.Attribute("cat") == 1
select item.Attribute("owner")).Distinct();
Apologies for formatting and indentation!

Try this function:-
static IEnumerable<int> GetOwners(XDocument doc, string cat)
{
return from item in doc.Descendants("item")
where item.Attribute("cat").Value == cat
select (int)item.Attribute("owner")).Distinct();
}

XElement ele = XElement.Parse(#"<items><item cat=""1"" owner=""14"">bla</item><item cat=""1"" owner=""9"">bla</item>" +
#"<item cat=""1"" owner=""14"">bla</item><item cat=""2"" owner=""12"">bla</item>" +
#"<item cat=""2"" owner=""12"">bla</item></items>");
int cat = 1;
List<int> owners = ele.Elements("item")
.Where(x=>x.Attribute("cat").Value==cat.ToString()).Select(x=>Convert.ToInt32(x.Attribute("owner").Value)).Distinct().ToList();