linq中如何在join中指定多个条件

public ActionResult Edit(int id)
{
using (DataContext db = new DataContext(ConfigurationManager.ConnectionStrings["sqlConnection"].ConnectionString))
{
IQueryable<ClassInformation> result = from c in db.GetTable<TClass>()
join t in db.GetTable<TTeacher>()
on new { id = c.ID, id1 = c.ID }
equals new { id = t.ClassID, id1 = id }
select new ClassInformation { ID = c.ID, ClassID = t.ClassID, Name = c.Name, TeacherName = t.Name, Address = t.Address, Phone = t.Phone, Email = t.Email };
ClassInformation k = result.Single();
ViewData["K"] = k;
return View();

}

}