WF - ActivityExecutionContext in While Activity

I have a SequentialActivity that also contains a WhileActivity. In the while activity I want to call开发者_如何学Python a method from a service - if it returns true I execute a delay activity, otherwise I continue with workflow execution, therefore I need to retrieve the service using the GetService method. How can I access the execution context from the code condition of the while activity? (WF 3.5)

You can't and will need to either create a custom activity or put the code in some other function that you can call from a VB expression.