static TextRuleViewModel() { CompositionContainerProvider compositionContainerProvider = new CompositionContainerProvider(); CompositionContainer container = compositionContainerProvider.GetInstance(); _whenNames = container.GetDistinctExportsTypes(typeof(ITextRuleOperationModel), typeof(WhenViewModel)).GetAttributes <DescriptionAttribute>().Select(attr => attr.Description).ToList(); _thenNames = container.GetDistinctExportsTypes(typeof(ITextRuleOperationModel), typeof(ThenViewModel)).GetAttributes <DescriptionAttribute>().Select(attr => attr.Description).ToList(); }