public void SettingOutAndRefParameters() { var method = typeof(IMyInterface).GetMethod("MethodWithOutAndRefValues"); invocationInterceptor.OnInvocationHandler = invocation => { Assert.AreEqual(42, (int)invocation.ParameterValues[0]); invocation.ParameterValues[0] = 43; invocation.ParameterValues[1] = 44; }; var parameters = new object[] { 42, null }; Invocation.HandleInvocation(target, InvocationFactory.GetForMethod(method), null, parameters, null); Assert.AreEqual(43, parameters[0]); Assert.AreEqual(44, parameters[1]); }