title: Blank/Empty WSDL file
body: <p>I'm struggling to have my WCF web service output a wsdl file with no luck so far (it's empty?).</p>
  
  <p>the svc file:</p>
  
  <pre><code>&lt;%@ ServiceHost Language="C#" Debug="true" Service="xxx.WCF.SubsetMID" CodeBehind="SubsetMID.svc.cs"
  Factory="System.ServiceModel.Activation.WebServiceHostFactory"
  %&gt;
  </code></pre>
  
  <p>the cs file :</p>
  
  <pre><code>namespace xxx.WCF
  {
      [ServiceContract(Namespace = "SubsetMID")]
      public interface ISubsetMID
      {
          [OperationContract]
          [WebInvoke(BodyStyle=WebMessageBodyStyle.Wrapped)]
          long[] GetMIDs(Guid guid, int subsetID);
      }
  
      [DataContract]
      [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Required)]
      public class SubsetMID : ISubsetMID
      {
          public long[] GetMIDs(Guid guid, int subsetID)
          {
              [...]
  
              return returnValue;
          }
      }
  }
  </code></pre>
  
  <p>My web config file :</p>
  
  <pre><code>&lt;system.serviceModel&gt;
    &lt;services&gt;
      &lt;service name="xxx.WCF.SubsetMID"&gt;
        &lt;endpoint address=""
                  binding="wsHttpBinding"
                  contract="xxx.WCF.ISubsetMID" /&gt;
  
        &lt;endpoint address="mex"
                  binding="mexHttpBinding"
                  contract="IMetadataExchange" /&gt;
      &lt;/service&gt;
    &lt;/services&gt;
    &lt;behaviors&gt;
      &lt;serviceBehaviors&gt;
        &lt;behavior&gt;
          &lt;serviceMetadata httpGetEnabled="true" /&gt;
        &lt;/behavior&gt;
      &lt;/serviceBehaviors&gt;
    &lt;/behaviors&gt;
    &lt;serviceHostingEnvironment
        multipleSiteBindingsEnabled="true"
        aspNetCompatibilityEnabled="true"
    /&gt;
  &lt;/system.serviceModel&gt;
  </code></pre>
  
  <p>I don't get any error when I access the wsd (<code>http://.../SubsetMID.svc?wsdl</code>) but it's just a blank page.</p>