Error when building an XDocument

Question

Using the following example xml containing one duplicate:

<Persons>
  <Person>
    <PersonID>7506</PersonID>
    <Forename>K</Forename>
    <Surname>Seddon</Surname>
    <ChosenName />
    <MiddleName />
    <LegalSurname />
    <Gender>Male</Gender>
  </Person>
  <Person>
    <PersonID>6914</PersonID>
    <Forename>Clark</Forename>
    <Surname>Kent</Surname>
    <ChosenName>Clark</ChosenName>
    <MiddleName />
    <LegalSurname>Kent</LegalSurname>
    <Gender>Male</Gender>
  </Person>
  <Person>
    <PersonID>6914</PersonID>
    <Forename>Clark</Forename>
    <Surname>Kent</Surname>
    <ChosenName>Clark</ChosenName>
    <MiddleName />
    <LegalSurname>Kent</LegalSurname>
    <Gender>Male</Gender>
  </Person>
</Persons>

I have the following code where I am trying to build an XDocument with the output of an XPath query that filters the duplicate elements:

string outputXml = null;
var original = XDocument.Parse(xmlString);
string xpathFilterDups = "//Person[not(PersonID = following::Person/PersonID)]";
XDocument people = new XDocument("Persons", original.XPathSelectElements(xpathFilterDups));
outputXml = people.ToString();

I get the error:

An exception of type 'System.ArgumentException' occurred in System.Xml.Linq.dll but was not handled in user code

Non white space characters cannot be added to content.

On this line:

XDocument people = new XDocument("Persons", original.XPathSelectElements(xpath));

What am I doing wrong? :-\

Answer 1

You can ignore pretty much all your code, the issue is just this:

XDocument people = new XDocument("Persons");

You can't create an XDocument containing a string, you need to add an element:

XDocument people = new XDocument(
    new XElement("Persons",
        original.XPathSelectElements(xpathFilterDups)));