title: The specified type member 'Offset' is not supported in LINQ to Entities
body: <p>I got the exception when the next code run:</p>
  
  <pre><code> var fbPost = db.FacebookStatusUpdates
           .Where(f =&gt; 
                 f.FacebookUpdateTime - f.ClientTime.Offset &lt;= 
                 DateTimeOffset.Now.UtcDateTime - ConvertTimeSpan(f.Offset) &amp;&amp;
                 f.Status == FacebookNotificationStatus.Active &amp;&amp;
                 f.Alarm.User.FbStatus == true).ToList();
  </code></pre>
  
  <p>Exception message</p>
  
  <blockquote>
    <p>The specified type member 'Offset' is not supported in LINQ to Entities. Only 
    initializers, entity members, and entity navigation properties are
    supported.</p>
  </blockquote>
  
  <p>My model:</p>
  
  <pre><code> public class FacebookStatusUpdate
   {
      public long Id { get; set; }
      public DateTime FacebookUpdateTime { get; set; }
      public string PostId { get; set; }
      public DateTime? FacebookPostTime { get; set; }
      public DateTimeOffset ClientTime { get; set; }
      public int Offset { get; set; }
  
      public virtual FacebookNotificationStatus Status { get; set; }
      public virtual Alarm Alarm { get; set; }
  }
  </code></pre>
  
  <p>Can somebody help me?</p>