Event Aggregator in Prism 4.0 with MEF

Today I am going to share a simple trick about Event Aggregator, I was working in one of my project and I was trying to use event aggregator. I was stopped by a show stopper exception, and couldn’t find out what is going on. here is the expectation that I had.

Looks familiar? I bet some of you had encounter it. well the solution is pretty easy while subscribing an event you got to also set your thread option and off course a true value to keep reference alive parameter of the subscribe method.

public InboxViewModel(IEventAggregator eventAggregator)
{
            _eventAggregator = eventAggregator;
            var myDemoEvent = _eventAggregator.GetEvent<MyDemoEvent>();
            if (myDemoEvent != null)
                myDemoEvent.Subscribe(OnEvent,ThreadOption.UIThread,true);
}
private void OnEvent(MyCustomObject obj)
{
     //do some thing over here            
}

I already assume that you know about how to make a custom event for Event aggregator. If not here is a code sample. The main catch is that it have to be inherited from CompositePresentationEvent<>. The code sample is given bellow.

 public class MyDemoEvent:CompositePresentationEvent<MyCustomObject>
    {
        //here goes thing about your cutom event
    }

    public class MyCustomObject
    {
        //here goes you custom event payload stuff
    }

Till next post happy programming.