Question

I have an issue while trying to parse an Xml to Objects using Linq in a Windows Phone 7 application. The same linq query works in silverlight.

Here is the xml:

<?xml version="1.0" encoding="utf-8" ?>
<students>
  <student>
    <firstName>John</firstName>
    <lastName>Doe</lastName>
  </student>
  <student>
    <firstName>Jane</firstName>
    <lastName>Doe</lastName>
  </student>
</students>

And all the code that I have is in the MainPage.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;
using System.Xml.Linq;

namespace WindowsPhoneApplication2
{
    public class Student
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }

    public partial class MainPage : PhoneApplicationPage
    {
        // Constructor
        public MainPage()
        {
            InitializeComponent();

            XDocument doc = XDocument.Load("my1.xml");

            var test = from students in doc.Elements("students").Elements("student")
                       select new Student()
                       {
                           FirstName = students.Element("firstName").Value,
                           LastName = students.Element("lastName").Value
                       };

            foreach (var _student in test)
            { }
        }
    }
}

The error that I get is pretty weird (this is inside the foreach when you quick watch test):
System.Collections.Generic.IEnumerator.Current = Could not evaluate expression.
System.Collections.Generic.IEnumerator.Current = ‘System.Collections.Generic.IEnumerable’ does not contain a definition for ‘System’ and no extension method ‘System’ accepting a first argument of type ‘System.Collections.Generic.IEnumerable

In the mean time inside the foreach the _student var has the correct value on each iteration?! Is this error a bug? Or where is it coming from?

… :\

Edit:

Here is a screenshot of where I see the error:

The students collection turn out to be correct but having that error there frightens me for when i will push out an application to the App Market.

If it helps i am using the emulator to debug.

EDIT:
I’m adding this screenshot based on Desnnis’s response.

Answer 1

First of all add a reference to System.Linq in the class header. As in:

using System.Linq;

The problem in your case is that you are setting the breakpoint at the beginning of the foreach loop when nothing is selected. Create an action inside the loop and set a breakpoint there. You will see that the values will have a Student instance.