System.EngineExecutionException on a return from a WCF service

Question

This one has us all baffled at work. We have two services running on .net 3.5 SP1 that hits up sharepoint, and return Lists of model objects that are pretty similar. One of them works fine, the other throws an EngineExecutionException on the return.

I know that is sort of vague, but everything executes fine right up until that point. When you look at the List in the debugger, everything looks pretty normal.

Has anyone had this happen before? If so, what did you do to work around it?

Answer 1

Ok, it turns out that if you have ILists in your data contract, the framework blows up. Change IList to List as your return type, and it works