public void DeleteAbbreviations(IList <Object> selectedAbbreviations)
 {
     if (SelectionMode)
     {
         if (selectedAbbreviations.Count() > 0)
         {
             List <Abbreviation> list = new List <Abbreviation>();
             foreach (var item in selectedAbbreviations)
             {
                 list.Add((Abbreviation)item);
             }
             _abbreviations.DeleteAbbreviations(list);
             OnPropertyChanged("AbbreviationCollection");
         }
     }
 }