title: ?: and ?? Operators with Entity Framework
body: <p>Why these operators does not work within these examples?</p>
  
  <pre><code>person.CityName = personInfo.Cities.CityName ?? "-"; 
  </code></pre>
  
  <p>or</p>
  
  <pre><code>person.CityName = personInfo.Cities.CityName == null ? "-" : personInfo.Cities.CityName; 
  </code></pre>
  
  <p>View generates System.NullReferenceException. If they are not allowed what do you advice?</p>