title: How to get Users who only have some specific department id, Linq
body: <p>I have following two entities</p>
  
  <pre><code>public class User
  {
     public int UserId { get; set; }
     public string UserName { get; set; }
     public List&lt;Department&gt; Departments { get; set; }
  }
  
  public class Department
  {
     public int DepartmentId { get; set; }
     public string DepartmentName { get; set; }
     public List&lt;User&gt; Users { get; set; }
  }
  </code></pre>
  
  <p>As you see, relationship between two objects is M:N.
  I wanna get User who only have specific department ID, in this case, How to get users using Linq?</p>
  
  <p>Thanks in advance</p>