Newcomers to the WCF Adapters in BizTalk Server 2006 R2 must be aware of two “gotchas” that they're likely to face when sending or receiving WCF messages with the adapters.
The first gotcha is that the IsOneWay property of operation contracts must be false. Luckily IsOneWay is false by default, but developers sometimes set it to true in an attempt to improve performance.
But the BizTalk WCF adapters always set IsOneWay to false, and so will fail whenever sending to or receiving from a client or service that has IsOneWay = true. (There’s an exception for the NetMsmq adapter.) Details about the errors you’ll receive are in the BizTalk documentation here.
The simple solution is to set IsOneWay back to false on your client or service. If you’re able to do that, the problem goes straight away.
If not – if for instance you lack authority to change the service contract – then you’ll have to put a wrapper service between BizTalk and the real service which, you guessed it, has the same WCF contracts as the real service except that IsOneWay is always false. This can be a pain, though it’s not hard to understand what you’re doing.
The second gotcha requires some deeper knowledge of WCF, so I’ll save it for the next post.