private void Search(string searchedWord) { searchedWord = searchedWord.ToLower(); int wordLength = searchedWord.Length; // CurrentPatients = new ObservableCollection<PatientViewModel>(PatientsList.Where(item => item.Name.ToLower().Contains(searchedWord))); CurrentPatients = new ObservableCollection <LocalPatient>(PatientsList.Where(item => (item.Name != null && item.Name.Length >= wordLength && item.Name.ToLower().Substring(0, wordLength) == searchedWord) || item.Surname != null && item.Surname.Length >= wordLength && item.Surname.ToLower().Substring(0, wordLength) == searchedWord)); SelectedPatient = CurrentPatients.FirstOrDefault(); }