title: the System.ComponentModel.DataAnnotations namespace does not exist
body: <p>I used <code>ASP.NET MVC 5.2</code> and <code>EF 6</code> and <code>.Net 4.6</code> in Visual studio <code>2013</code>.</p>
  
  <p>Iadded <code>System.ComponentModel.DataAnnotations</code> <code>dll</code> but when I want add this namespace in my project It does not exist. </p>
  
  <p>I just have <code>System.ComponentModel.Design</code> namespace in classes.</p>
  
  <p>I have dll in refrences .</p>
  
  <p>whats wrong ?</p>