title: How can I enter in date and username automatically when updating storage?
body: <p>I have the following class that's used by my MVC3 application. I would like
  to simplify the updating of the class so that when a new class object is 
  created then the Created and CreatedBy fields get set automatically. </p>
  
  <p>I'd also like to make it so that the Modified and ModifiedBy fields get 
  updated automatically. </p>
  
  <p>Is there a way that I could do this?</p>
  
  <pre><code>The class is used in MVCnamespace Storage.Models
  {
      public class Topic : TableServiceEntity
      {
          [DisplayName("Partition Key")]
          public override string PartitionKey { get; set; }
          [DisplayName("Row Key")]
          public override string RowKey { get; set; }
          [DisplayName("Description")]
          public string Description { get; set; }
          public DateTime Created { get; set; }
          public DateTime Modified { get; set; }
          public String CreatedBy { get; set; }
          public string ModifiedBy { get; set; }
      }
  }
  </code></pre>