title: WCF: "IsRequired" property for DataMember with "IsReference" property for DataContract
body: <p>Why does WCF does not allow to set the "IsRequired" property for DataMembers when I set the "IsReference" property for the DataMember's DataContract? And is there a way to solve this problem?</p>
  
  <pre><code>    [DataContract(IsReference = true)]
      public class MyClass
      {
          private DateTime date;
  
          [DataMember (IsRequired = true)]
          public DateTime Date
          {
              get { return date; }
              set { date = value; }
          }
      }
  </code></pre>
  
  <p>This code will create an error because "IsReference" and "IsRequired" are set.</p>