public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture) { ReadOnlyObservableList <QueueListItem> crawlingQueuelistItem = (ReadOnlyObservableList <QueueListItem>)values[0]; IBlog currentQueuelistItem = (IBlog)values[1]; if (crawlingQueuelistItem.Any(item => item.Blog.Name.Equals(currentQueuelistItem.Name) && item.Blog.BlogType.Equals(currentQueuelistItem.BlogType))) { return(true); } return(false); }