public ServiceProvider() { var fooService = new FooService(); var barService = new BarService(); Handlers = new Dictionary <Type, Action <object> > { { typeof(FooRequestA), request => fooService.ProcessA((FooRequestA)request) }, { typeof(FooRequestB), request => fooService.ProcessB((FooRequestB)request) }, { typeof(BarRequest), request => barService.Process((BarRequest)request) } }; }