"Plug-in framework Discovery series" Establishing a subscription publishing mechanism based on delegates

Some time ago, there was an idea if you want to put together something that you feel is interesting and easy to develop, build a framework that will make it easier to develop, but later, as more things become involved, it's more and more likely that it's not something a developer needs because it's too miscellaneous, yes, As a framework, or simple point of good, and later work is busy, it stalled. These days on business trip to Guangzhou, night to have nothing to do, then pick up a module to say that said.

Messenger

In peacetime development, data transfer, processing, etc. can be done through the event mechanism, but the event mechanism will introduce coupling, of course, this coupling is often reasonable, but there are some times this coupling is not what you need, too much reliance will make you confused, The introduction of Messenger is to remove this dependency, please look at the figure below.

Figure 1. One-way dependencies between classes

Figure 2. Bidirectional dependencies between classes

Figure 3. Dependencies after the introduction of Messenger

Messenger's concept from the MVVM Foundation project, after reading the project's source code, found that the messenger is a good mechanism, based on this mechanism and the actual design of their own messenger.

As the name implies, Messenger is here as the executor of the Act, whose duty is to subscribe to the Act of pre acceptance, to perform these actions when needed, i.e. publish.

Figure 4. Messenger class diagram