Serialization Exception when attempting to receive Azure Service bus message via Topic/Subscriptions

Question

I am recieving a Serialization Exception when attempting to parse the messaage recieved when subscribed to an Azure Service Bus topic. Anyone see what I am missing? I am using the Microsoft.ServiceBus.Samples.Messaging for the the Silverlight code.

I have a webservice with the following code:

public void PushCommand(Command command, int posLocationId)
{
    var topicName = "topicName";
    var topicClient = TopicClient.CreateFromConnectionString(ConnectionString, topicName);

    try
    {
         var message = new BrokeredMessage("test");
         topicClient.Send(message);
    }
    ...
}

I have a SilverLightClient with the following code:

private void OnReceiveMessageCompleted(IAsyncResult result)
{
     var subscriptionClient = (SubscriptionClient)result.AsyncState;
     try
     {
         var message = subscriptionClient.EndReceive(result);

         if (message != null)
         {
             String s = message.GetBody<string>();
         }

         // prep for next message
         subscriptionClient.BeginReceive(this.OnReceiveMessageCompleted, subscriptionClient);

     }
     catch (Exception e)
     {
        //unknown error
     }
}

SerializationException was caught There was an error deserializing the object of type System.String. Data at the root level is invalid. Line 1, position 1.

Stacktrace:

at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName)
at System.Runtime.Serialization.XmlObjectSerializer.ReadObject(XmlDictionaryReader reader)
at System.Runtime.Serialization.XmlObjectSerializer.ReadObject(Stream stream)
at Microsoft.Samples.ServiceBus.Messaging.BrokeredMessage.GetBody[T]()
at Common.SubscriptionManager.OnReceiveMessageCompleted(IAsyncResult result)

Answer 1

The issue isn't in your SL code, it's in your sender code. When sending the message, the default implementation uses a binary message serializer, but the SL implementation uses DataContractSerializer, which depends on XML formatted messages. To fix the issue, your message send needs to do something like this:

DataContractSerializer ser = new DataContractSerializer(typeof(string));
queueClient.Send(new BrokeredMessage("test", ser));

On Service Bus, the body content is pretty much a bag of bytes-- the sender and receiver need to agree on how those things will be encoded/decoded.

Answer 2

You can serialize the string and send it as byte stream and at the receiving end you can deserialize to string. It will work.