无法提取元素（通过元素名称AND属性）

Question

I have the following XML sample which I need to parse in order to extract parameters:

    <?xml version="1.0" encoding="UTF-8"?>
<bulkCmConfigDataFile xmlns:un="utranNrm.xsd"  xmlns:xn="genericNrm.xsd" xmlns:gn="geranNrm.xsd"  xmlns="configData.xsd" 
 xmlns:es="Vendor1SpecificAttributes.1.0.xsd">
    <fileHeader fileFormatVersion="1.0" vendorName="Vendor1"/>
    <configData dnPrefix="Undefined">
        <xn:SubNetwork id="ONRM_ROOT_MO_R">
            <xn:SubNetwork id="RNC0001">
                <xn:MeContext id="BLABLA">
                </xn:MeContext>
                <xn:MeContext id="MACHIN">
                </xn:MeContext>
                <xn:MeContext id="RNC0001">
                    <xn:VsDataContainer id="RNC0001">
                    </xn:VsDataContainer>
                    <xn:ManagedElement id="1">
                        <un:RncFunction id="1">
                            <un:UtranCell id="111111A">
                                <un:attributes>
                                    <un:uarfcnUl>9800</un:uarfcnUl>
                                    <un:uarfcnDl>10700</un:uarfcnDl>
                                </un:attributes>
                                <xn:VsDataContainer id="111111A">
                                    <es:Position>
                                    <es:latitudeSign>1</es:latitudeSign>
                                    <es:latitude>3070727</es:latitude>
                                    <es:longitude>8786820</es:longitude>
                                    </es:Position>
                                </xn:VsDataContainer>
                                <xn:VsDataContainer id="1">
                                </xn:VsDataContainer>
                            </un:UtranCell>
                            <un:UtranCell id="111111B">
                                 <un:attributes>
                                    <un:uarfcnUl>9800</un:uarfcnUl>
                                    <un:uarfcnDl>10700</un:uarfcnDl>
                                </un:attributes>
                                <xn:VsDataContainer id="111111B">
                                    <es:Position>
                                    <es:latitudeSign>1</es:latitudeSign>
                                    <es:latitude>3070555</es:latitude>
                                    <es:longitude>8786666</es:longitude>
                                    </es:Position>
                                </xn:VsDataContainer>
                                <xn:VsDataContainer id="1">
                                </xn:VsDataContainer>
                            </un:UtranCell>
                        </un:RncFunction>
                    </xn:ManagedElement>
                </xn:MeContext>
            </xn:SubNetwork>
        </xn:SubNetwork>
    </configData>
    <fileFooter dateTime="2011-11-28T08:38:45Z"/>
</bulkCmConfigDataFile>             

So far I've only been able to retrieve the first element by name for a given namespace:

XNamespace xn = "genericNrm.xsd";
XNamespace un = "utranNrm.xsd";
var test1 = xmldoc.Descendants(xn + "MeContext").FirstOrDefault();

which will only give me the first Element "MeContext" (in this example this will return the MeContext with id=BLABLA).

If I try the following instead

XNamespace xn = "genericNrm.xsd";
XNamespace un = "utranNrm.xsd";
var test1 = xmldoc.Descendants(xn + "MeContext");

test1 will be null ...

1 - My first question is how do I retrieve a specific element using its "id" attribute (in this specific example I'm looking for the id="RNC0001"). I tried many things coming from stackoverflow including the following:

XNamespace xn = "genericNrm.xsd";
IEnumerable<XElement> utrancells =
                            xmldoc.Root
                                    .Elements(xn + "MeContext")
                                    .Where(el => (string)el.Attribute("id") == "RNC0001");

which only returns null values.

2 - The second problem is how to retrieve a collection of elements from the <xn:MeContext id="RNC0001"></xn:MeContext> ? I would like to get all the <un:UtranCell id="XXXXX"></un:UtranCell> (and content) in a collection so I can extract data from each of them (each represent a different entity). For instance I need to retrieve

<es:latitude>3070555</es:latitude>
<es:longitude>8786666</es:longitude>

from each <un:UtranCell id="XXXXX"></un:UtranCell>

For this I tried (as a test):

XNamespace un = "utranNrm.xsd";
var test3 = xmldoc.Elements(un + "UtranCell");
var test4 = test1.Elements(un + "UtranCell");

and again it returns only null values ...

Edit for Daniel: The real code is:

public void parseFile()
{
    XNamespace xn = "genericNrm.xsd";
    XNamespace un = "utranNrm.xsd";
    XNamespace cd = "configData.xsd";

    var test1 = xmldoc.Descendants(xn + "MeContext").FirstOrDefault();
    var test1bis = xmldoc.Descendants(xn + "MeContext");
}

This gives me: test1 = <xn:MeContext id="BLABLA" xmlns:xn="genericNrm.xsd"></xn:MeContext>

test1bis = {System.Xml.Linq.XContainer.GetDescendants} | name = null

Answer 1

The problem in both cases is that you are using Elements instead of Descendants . The difference is that Elements only returns those elements that are immediate children - ie one level deep, whereas Descendants searches the entire subtree. Try this instead:

IEnumerable<XElement> utrancells =
    xmldoc.Root
          .Descendants(xn + "MeContext")
          .Where(el => (string)el.Attribute("id") == "RNC0001");