SimpleIoc.Default.Register fails at IsInDesignModeStatic if the Interface is in different assembly

Question

In the static constructor of ViewModelLocator class the SimpleIoc.Default.Register(); fails at IsInDesignModeStatic mode, if

Answer 1

    if (ViewModelBase.IsInDesignModeStatic) {


        // put these lines here:
        if (SimpleIoc.Default.IsRegistered<IDataService>()) {
            SimpleIoc.Default.Unregister<IDataService>();
        }

        SimpleIoc.Default.Register<IDataService, Design.DesignDataService>();
    }
    else {
        SimpleIoc.Default.Register<IDataService, DataService>();
    }