c# - Why does IDependecyResolver.Resolve<IUICompositionService>() method throw exception 'Catel.IoC.TypeNotRegisteredException'? -

i have exception 'catel.ioc.typenotregisteredexception' when try resolve iuicompositionservice interface. added reference catel.extensions.prism , installed loadassembliesonstartup.fody nuget wpf mvvm catel project , in app.xaml.cs in app.onstartup() method wrote following code:

var servicelocator = new servicelocator(); servicelocator.registertypesusingdefaultnamingconvention(); 

in mainwindowviewmodel in command method wrote following code visualizing calibrationview view in application mainwindow:

private void showcalibrationviewexecute() {     var viewmodel = new calibrationviewmodel();     var dependencyresolver = this.getdependencyresolver();     var uicompositionservice = dependencyresolver.resolve<iuicompositionservice>();     uicompositionservice.activate(viewmodel, "mainregion"); } 

for view there calibrationmodel , calibrationviewmodel classes in application. when press showcalibrationview button in mainwindow toolbar , showcalibrationviewexecute method calls in line

var uicompositionservice = dependencyresolver.resolve<iuicompositionservice>(); 

exception catel.ioc.typenotregisteredexception thrown. exception reports: the specified type 'catel.services.iuicompositionservice' not registered or not constructed. please register type before using it. type 'catel.services.iuicompositionservice' not registered. how can correct , eliminate error? i'm doing wrong?

p.s. have followin catel's references in project: catel.core, catel.extensions.controls, catel.extensions.prism, catel.fody.attributes, catel.mvvm.

make sure implement bootstrapper takes care of type registration. check out examples in examples repository, contains several prism examples.