title: How to validate GET url parameters through ModelState with data annotation
body: <p>I have a Web API project... I would like to respect the REST principles, so I should have just a GET method and just a POST method... 
  I have to do a search, so i think this matches the GET method, because after the search I obtain the result and I show it in the page... If I do not find anything I must create the object... this action is a POST... </p>
  
  <p>Now I have a problem... I must validate the filters of the search, because filters are a tax code and a alpha-numeric code (6 chars)... I have already done a client side validation. Now I should do a Server Side validation.</p>
  
  <p>Untill now, we have used data annotation to validate the request, but this is a GET... so my method has this signature:</p>
  
  <pre><code>[HttpGet]
  public IHttpActionResult GetActivationStatus(string taxCode, string requestCode)
  {
      if (ModelState.IsValid)
      {
           ...
      }
  }
  </code></pre>
  
  <p>But how can I validate my ModelState with Data Annotation?</p>
  
  <p>Thank you</p>