static DispatchTuple createFromWidget <TView, TEventArgs>(Expression <Func <TView, object> > property, Action <TView, EventHandler <TEventArgs> > addHandler, Action <TView, EventHandler <TEventArgs> > removeHandler)
where TView : View
where TEventArgs : EventArgs
{
// ExpressionToPropertyNames is used here as it handles boxing expressions that might
// occur due to our use of object
var propName = property.Body.GetMemberInfo().Name;
return(new DispatchTuple {
Type = typeof(TView),
Property = propName,
Func = (x, ex) => {
var v = (TView)x;
return Observable.FromEventPattern <TEventArgs>(h => addHandler(v, h), h => removeHandler(v, h))
.Select(_ => new ObservedChange <object, object>(v, ex));
}
});
}
private static DispatchTuple CreateFromAdapterView()
{
// AdapterView is more complicated because there are two events - one for select and one for deselect
// respond to both
const string propName = "SelectedItem";
return(new DispatchTuple
{
Type = typeof(AdapterView),
Property = propName,
Func = (x, ex) =>
{
var v = (AdapterView)x;
return Observable.Merge(
Observable.FromEventPattern <AdapterView.ItemSelectedEventArgs>(h => v.ItemSelected += h, h => v.ItemSelected -= h)
.Select(_ => new ObservedChange <object, object>(v, ex)),
Observable.FromEventPattern <AdapterView.NothingSelectedEventArgs>(h => v.NothingSelected += h, h => v.NothingSelected -= h)
.Select(_ => new ObservedChange <object, object>(v, ex)));
}
});
}
