Undefined Object Reference for an object instance when trying to retrieve an element in an XML file

Question

I’m making a mistake tormenting myself.

Basically I am saving all equipment settings (RF Readers) in an XML file (Configs.xml). My goal is to retrieve the first element of all settings that have a "set" value (other than "") in the new attributeLote. If the recovered element is different from null I proceed with the code within the IF, otherwise I will release an exception. However, the code below gives the following error when I am trying to retrieve the element(third line): Object Reference not defined for an instance of an object.

Can anyone tell me what I’m doing wrong? Thanks!

XElement xml = XElement.Load("Configs.xml");
XElement x = null;
x = xml.Elements().Where(p => !p.Attribute("novoLote").Value.Equals("")).FirstOrDefault();
if (x != null)
{
    ...
}
else
{
    throw new ReaderNaoConfiguradoParaFuncaoException("Nenhum Reader está configurado para essa função.");
}

Answer 1

This can be simplified to:

x = xml.Elements().FirstOrDefault(p => !p.Attribute("novoLote").Value.Equals(""));

Still, it is prone to errors. You can improve the sentence to:

x = xml.Elements().FirstOrDefault(p => p.Attribute("novoLote").Value != null && !p.Attribute("novoLote").Value.Equals(""))