Hit by CS1911 when trying to use non-generic overload of Observable.FromEvent

Question

Example code:

public static IObservable<IEvent<MouseEventArgs>> GetMouseDown(this Control control)
{
    return Observable.FromEvent<MouseEventHandler, MouseEventArgs>(
        h => new MouseEventHandler(h),
        h => control.MouseDown += h,
        h => control.MouseDown -= h
        );
}

CS1911: "Access to member 'System.EventHandler<TEventArgs>.Invoke(object, TEventArgs)' through a 'base' keyword from an anonymous method or iterator results in unverifiable code. Consider moving the access into a helper method on the containing type."

I know this is fixed in the C#4.0 compiler, but I'm playing in 3.5 and VS2008.

Anyone know if this slipped through the net? Or if I'm doing something wrong? Or if there is a workaround?

Answer 1

Hi Benjol,

this will get rid of the warning:

 

return Observable.FromEvent<MouseEventHandler, MouseEventArgs>(

h => (o,e)=>h(o,e),

h => control.MouseDown += h,

h => control.MouseDown -= h

);

Regards,


Jeffrey

Answer 2

Thanks,

and

ouch! my brain.