Communication between several add-ons

.Net Add-on Programming
1

There are two .net Add-ons. Both are IDockableScreens. What is the cleanest way to communicate between both add-ons ? I thought about events at the beginning, but to register for events of the other add on, you need an instance of the add on which fires the event. Is there a way to access the add-on instances?
Or is it a common way to realize an event broker via an IPlugin project to handle the event handling?

All suggestions welcome :slight_smile:

2

You could use IEventAggregator which you can import, implement IHandle<T> and subscribe to the aggregator to get messages of type T.

However, I would just define some interface IMyInterface in one of the add-ons and export a shared instance of it, then just import that in the other add-ons.

So something like this (example only, written from memory):

public interface IMyinterface
{
   // Add some useful properties and methods.
}

[Export(typeof(IDockableScreen))]
[Export(typeof(IMyInterface))]
[PartCreationPolicy(CreationPolicy.Shared)]
internal class MyDockable : Screen, IMyInterface
{
   // Implement.
}

[Export(typeof(IDockableScreen))]
internal class MyOtherDockable : Screen
{
   [ImportingConstructor]
   public MyOtherDockable(IMyInterface myDockable)
   {
       // Do something with the other dockable.
   }
}

If you want to do some kind of plugin system of your own, you can have many implementations of some interface exported and [ImportMany] them, or use IoC.GetAll<T>()

3

Thanks, the variant with the interface works well for my use case. Thank you for the quick support.