title: Changing dbContext at runtime
body: <p>I have a UsersContext : DbContext with a DbSet Users { get; set; }</p>
  
  <p><strong>UsersController.cs</strong></p>
  
  <pre><code>public class UsersController : Controller
  {
     private UsersContext db = new UsersContext("dbA");
  
     public ViewResult Index()
     {
         if (...)
            db = new UsersContext("dbA");
         else
            db = new UsersContext("dbB");
         return View(db.Users.ToList());
     }
  }
  </code></pre>
  
  <p>This returns the good associated list.<br/>
  If I choose dbB I have the good list but when I go on detail on one of the results in :</p>
  
  <pre><code>public ViewResult Details(int id)
  {
     User user = db.Users.Find(id);
     return View(user);
  }
  </code></pre>
  
  <p>The db's connectionString is associated to the dbA not the dbB.
  Why the new db is not well initilized and saved ?</p>