public View1ViewModel()
        {
            contactesPopulate();
            GridContactes = new ObservableCollection<contacte>(db.contactes.ToList());
            FilteredContactes = GridContactes;
        }

        private ObservableCollection<contacte> _gridContactes;
        public ObservableCollection<contacte> GridContactes
        {
            get
            {
                return _gridContactes;
            }
            set
            {
                if (_gridContactes == value)
                    return;

                _gridContactes = value;
                NotifyPropertyChanged();
            }
        }

        private ObservableCollection<contacte> _filteredContactes;
        public ObservableCollection<contacte> FilteredContactes
        {
            get
            {
                return _filteredContactes;
            }
            set
            {
                if (_filteredContactes == value)
                    return;

                _filteredContactes = value;
                NotifyPropertyChanged();
            }
        }

        private void Filter()
        {
            _filteredContactes.Clear();
            foreach (contacte c in _gridContactes)
            {
                if (c.cognoms.Contains("a"))
                {
                    _filteredContactes.Add(c);
                }
            }
        }

        public const string TextFilterPropertyName = "TextFilter";
        private string _TextFilter;
        public string TextFilter
        {
            get { return _TextFilter; }
            set
            {
                _TextFilter = value;
                NotifyPropertyChanged();
                Console.WriteLine("filtering");
                Filter();
            }
        }