title: The ObjectContext instance has been disposed and can no longer be used for operations that require a connection. in Reference table
body: <p>I have two tables <strong>Customers</strong> and <strong>Country</strong> and use ( Entity Framework with vs 2012 )</p>
  
  <p><img src="https://i.stack.imgur.com/t5wd3.jpg" alt="enter image description here"></p>
  
  <p>And the model class </p>
  
  <pre><code> using System;
   using System.Collections.Generic;
  
   public partial class Customer
   {
       public int Id { get; set; }
       public string FirstName { get; set; }
       public string LastName { get; set; }
       public string Address { get; set; }
       public string Email { get; set; }
       public string Phone { get; set; }
       public Nullable&lt;int&gt; CountrryId { get; set; }
       public string Note { get; set; }
  
       public virtual Country Country { get; set; }
   }
  </code></pre>
  
  <p><strong>I try to build a select query for get all customers with Country Name.</strong> But I always get the below error message. </p>
  
  <p><img src="https://i.stack.imgur.com/u09Rk.jpg" alt="enter image description here"></p>