protected override void Init()
 {
     _command = For<IChangeTypeToNullCommand>();
     _source = For<ClassifierSelectionItemsSource>();
     _source.ByName(Dummy).Returns(_dummyClassifier); // the control contains the one classifier
     _selectClassMixin = new SelectClassifierWithNullItemMixin(_source, _command);
 }
 public SelectClassifierWithNullItemMixin(
     IClassifierSelectionItemsSource itemsSource,
     IChangeTypeToNullCommand command):
         base(itemsSource,command)
 {
     _command = command;
 }