aster File.Exists / FileInfo.Exists / Directory.Exists

privatestaticboolVerifyFileExists(Uri uri, inttimeout)
    vartask = newTask<bool>(() =>
        varfi = newFileInfo(uri.LocalPath);
    returntask.Wait(timeout) && task.Result;

LINQ: dot notation equivalent for JOIN

Consider this LINQ expression written using query notation:

List<Person> pr = (from p in db.Persons
                     join e in db.PersonExceptions
                     on p.ID equals e.PersonID
                     where e.CreatedOn >= fromDate
                     orderby e.CreatedOn descending
                     select p)

Question: how would you write this LINQ expression using dot notation?

List<Person> pr = db.Persons
                          p => p.ID,
                          e => e.PersonID,
                          (p, e) => new { p, e })
                    .Where(z => z.e.CreatedOn >= fromDate)
                    .OrderByDescending(z => z.e.CreatedOn)
                    .Select(z => z.p)

Note how a new anonymous type is introduced to carry both the p and e bits 
forward. In the specification, query operators which do this use transparent
identifiers to indicate the behaviour.