title: Entity Framework Connection Error "Cannot open database "DB" requested by the login. The login failed"
body: <p>I am using Entity Framework in .NET MVC 3.0 and use Code First method.
  And I used a .MDF file for database and also use "DropCreateDatabaseIfModelChanges" to generate database automatically after every change.</p>
  
  <p>My application works correct, but when I open database from Server Explorer in VS, then my application gives an error:</p>
  
  <blockquote>
    <p>Cannot open database "DB" requested
    by the login. The login failed. Login
    failed for user 'Mahdi-PC\Mahdi</p>
  </blockquote>
  
  <p>Could you help me?!</p>