How to automatically generating an extension method library of WPF Event - IObservable

Question

I almost exclusively use Reactive Extensions in my C# WPF apps these days. Adding and removing event handlers is an anti pattern and I'm completely jealous of the fact that F# events implement IObservable. To help C# developers the RX folks provide the below method ( and some others of varying type safeness ) ``` public static IObservable> FromEventPattern ( Action addHandler , Action removeHandler ) where TEventArgs : EventArgs ``` http://msdn.microsoft.com/en-us/library/hh211731(v=vs.103).aspx I would use it like so ``` var movingEvents = Observable.FromEventPattern(h => this.MouseMove += h, h => this.MouseMove -= h); ``` However this is tedious. What I'd like to be able to do is ``` var movingEvents = h.MouseMoveObserver(); ``` and be done with it. Such an extension method would look like ``` IObservable MouseMoveObserver(this Canvas This){ return Observable.From…

Accepted Answer

To get all the types deriving from FrameworkElement, you could use

```
var typesToDo = from t in Assembly.GetAssembly(typeof(FrameworkElement)).GetTypes()
                where t.IsSubclassOf(typeof(FrameworkElement)) 
                        && t.IsPublic 
                        && t.GetEvents().Any()
                select t;
```

and then you can use `type.GetEvents()` to get the events of each type. The EventInfo you get back will let you look at things like name, type, arguments etc.

You need to do a bit of extra work to cope with generic events, but it's not a huge amount.

I've put an example program up on GitHub along with an example of the output.

There is a risk that some of the output doesn't work properly, I haven't tried them all :) I did make sure they all build, and that at least some of them work correctly.

How to automatically generating an extension method library of WPF Event -> IObservable

Solution

Problem