Question

Please review below code and advice what needs to be done in order to get the additional last line in output as shown in expected output

class test {

   static void Main(string[] args)
    {

        XDocument doc = XDocument.Load("E:\\BI_analytics\\Data\\so.xml");
        var query = from test in doc.Descendants("tester")
                    from testreq in test.Descendants("testRequest")
                    from testresp in test.Descendants("testResponse")
                    let id = testreq.Element("id") == null ? string.Empty : testreq.Element("id").Value

                  //  select id;
                    from itm in testresp.Descendants("item")
                    select new
                    {
                        ID = (string)id,
                        Name = (string)itm.Attribute("itemname"),
                        Code = (string)itm.Attribute("itemocde"),
                    };


        foreach (var result in query)
        {
            Console.WriteLine(result);
        }
    }
}

Current output

{ ID = 2, Name = test item1, Code = 111 }
{ ID = 2, Name = test item2, Code = 222 }
{ ID = 3, Name = test item3, Code = 333 }
{ ID = 3, Name = test item4, Code = 444 }

Expected output

{ ID = 2, Name = test item1, Code = 111 }
{ ID = 2, Name = test item2, Code = 222 }
{ ID = 3, Name = test item3, Code = 333 }
{ ID = 3, Name = test item4, Code = 444 }
{ ID = 4, Name = , Code = }

<?xml version="1.0" encoding="utf-8"?>
<root>
  <tester>
    <testRequest>
      <id>2</id>
    </testRequest>
    <testResponse>
      <items>
        <item itemname="test item1" itemocde="111"/>
        <item itemname="test item2" itemocde="222"/>
      </items>
    </testResponse>
  </tester>
  <tester>
    <testRequest>
      <id>3</id>
    </testRequest>
    <testResponse>
      <items>
        <item itemname="test item3" itemocde="333"/>
        <item itemname="test item4" itemocde="444"/>
      </items>
    </testResponse>
  </tester>
  <tester>
    <testRequest>
      <id>4</id>
    </testRequest>
    <testResponse>
      <items />
    </testResponse>
  </tester>
</root>

Answer 1

This is the problem:

from itm in testresp.Descendants("item")

You don’t have any item elements, so you probably want:

from itm in testresp.Descendants("item").DefaultIfEmpty()

… at which point you need:

select new
{
    ID = (string)id,
    Name = itm == null ? "" : (string)itm.Attribute("itemname"),
    Code = itm == null ? "" : (string)itm.Attribute("itemocde"),
};