Class FlowBehaviorAttribute

The parameter must be of type FlowBehavior, and it must be ref or out. The compiler reads the variable after OnMethodEntryAdvice, OnMethodExceptionAdvice and OnMethodResumeAdvice. The value has no effect in the other advices.

With Return, the method returns the value assigned to the out or ref parameter bound by ReturnValueAttribute. When the advice has no such parameter, the method returns ReturnValue if the advice has a MethodExecutionArgs parameter, and the default value of its return type otherwise. In OnMethodExceptionAdvice, ThrowException throws the exception held by the out or ref parameter bound by ExceptionAttribute, which the advice can replace. Without such a parameter, it throws Exception or the caught exception, with a throw instruction, not a rethrow instruction. Yield requires a parameter bound by AwaiterAttribute.

In OnMethodExceptionAdvice, Continue behaves like Return. In an entry or resume advice of an async method, a parameter bound by this attribute without a parameter bound by AwaiterAttribute causes a build warning, because the advice cannot use Yield.

When the advice also has a MethodExecutionArgs parameter, the value of the parameter bound by this attribute is used, and FlowBehavior is ignored.