title: C# Json deserialize integer to type instance
body: <p>Consider the following json string given:</p>
  
  <pre><code>{
      "items":
      [
          { 
              ..., 
              "view_count":4,
              "answer_count":0,
              "score":0,
              "last_activity_date":1445071150
          }
      ],
      ...
  }
  </code></pre>
  
  <p>Is there a way to have <code>last_activity_date</code> deserialized as instance of another type using <code>System.Runtime.Serialization.DataContractAttribute</code> and <code>System.Runtime.Serialization.Json.DataContractJsonSerializer</code>?  </p>
  
  <p>E.g.: 1445071150 -> <code>Date</code> where <code>Date</code> is</p>
  
  <pre><code>[System.Runtime.Serialization.DataContract]
  public class Date
  {
      [System.Runtime.Serialization.IgnoreDataMember]
      public long ElapsedSeconds { get; set; }
  
      [System.Runtime.Serialization.IgnoreDataMember]
      public DateTime Date { get { ... } set; }
  
      public Date(long seconds)
      {
          ElapsedSeconds = seconds;
          Date = ...;
      }
  
      public static implicit operator Date(long seconds)
      {
          return new Date(seconds);
      }
  
      // Other members ...
  }
  </code></pre>