Upgrade-Guide from 2.8.5 to 3.0.0

As you updated your NuGet package yesterday, I updated it today in my application.

There are some major changes, where I’m not sure how to modify my code correctly.

A upgrade guide in your wiki would be very helpful (starting with your “BREAKING CHANGES”).

As for me: How to update from client.Disconnected += async (sender, args) { /* stuff to do when disconnected */ }; to your new client.DisconnectedHandler ?

… and why did you remove the good old style of the subscriptionresult.failure ?

Thanks so far

[chkr1011]

The reason is that event handlers are not fully compatible with async. So having them in the first place was wrong. The new approach is fully compatible with async. The new approach gives you 3 different ways on handling events.

1. Implement the required interface of a handler in your own class. You can do whatever you want. You can access fields. Inject stuff etc.
2. If you don’t need that and your handler is basically a one-liner you can use the “Delegate” classes which accept a async function.
3. If you don’t have async code you can still use the “Delegate” class because it also supports a not async method (Action instead of Func).

This gives you some flexibility. If you want to call multiple handlers you have to implement this on your own (create a new class and implement the required interface). This also allows you to deal with special use cases like stopping the event handler chain if one call fails or move data from the first handler to another one. This was all impossible when using event handlers.

[chkr1011]

Hi, basically some new namespaces were introduced. Visual Studio or Resharper should be able to import them properly.

For an example for handlers please read the Wiki. At the moment I have to time to put an upgrade guide together. Probably within the next days or weeks.

SubscriptionResult.Failure is now UnspecifiedError. This comes from new MQTTv5 specification where this value is renamed to the new value. So I had to decide to rely on Failure or move to UnspecifiedError. The strategy of this library is to provide a uniform API over MQTTv3.1 MQTTv3.1.1 and MQTTv5.0.0. So it becomes _UnspecifiedError now.

Best regards Christian