IList<Person> people = new List<Person>();
people.Add(new Person(){ Name = "Alan"});
people.Add(new Person(){ Name = "Bob"});
people.Add(new Person(){ Name = "Chris"});

Assert.That(people.All(....), "list of person not ordered correctly");

public static bool IsOrdered<T>(this IEnumerable<T> source)
{
  var comparer = Comparer<T>.Default;
  T previous = default(T);
  bool first = true;

  foreach (T element in source)
  {
      if (!first && comparer.Compare(previous, element) > 0)
      {
          return false;
      }
      first = false;
      previous = element;
  }
  return true;
}

public static bool IsOrdered<T>(this IEnumerable<T> enumerable) {
  var comparer = Comparer<T>.Default;
  using ( var e = enumerable.GetEnumerator() ) {
    if ( !e.MoveNext() ) {
      return true;
    }
    var previous = e.Current;
    while (e.MoveNext()) {
      if ( comparer.Compare(previous, e.Current) > 0) {
        return false;
      }
      previous = e.Current;
    }
    return true;
  }
}

var isOrdered = people.Select(x => x.Name).IsOrdered();

people.Zip(people.OrderBy(p => p.Name), (a, b) => a == b).All(eq => eq);

"Alan"  -- "Alan"  => true
"Bob"   -- "Bob"   => true
"Chris" -- "Chris" => true