protected static THandler GetHandler <THandler>(HandlerFactory factory) { THandler handler; try { handler = factory.GetInstance <THandler>(); } catch (Exception e) { throw new InvalidOperationException($"Error constructing handler for request of type {typeof(THandler)}. Register your handlers with the container. See the samples in GitHub for examples.", e); } if (handler == null) { throw new InvalidOperationException($"Handler was not found for request of type {typeof(THandler)}. Register your handlers with the container. See the samples in GitHub for examples."); } return(handler); }