我的列表框没有更新

我有一个列表框，我绑定HistoryItems，其中HistoryItems是History的ObservableCollection。下面是列表框的声明:

 <ListBox x:Name="RecentListBox" SelectionChanged="RecentListBox_SelectionChanged"   ItemsSource="{Binding HistoryItems,Converter={StaticResource HistoryValueConverter} }" ItemsPanel="{StaticResource ItemsPanelTemplate1_Wrap}" ItemTemplate="{StaticResource RecentViewModelTemplate}">

下面是History类:

public class History : INotifyPropertyChanged
    {
        public History() { }
        int _id;
        string _date;
        string _url;
        string _name;
        public History(int id, string date,string url,string name)
        {
            this.id = id;
            this.date = date;
            this.url = url;
            this.name = name;
        }
        public int id
        {
            get
            {
                return _id;
            }
            set
            {
                if (value != _id)
                {
                    _id = value;
                    NotifyPropertyChanged("id");
                }
            }
        }
        public string date
        {
            get
            {
                return _date;
            }
            set
            {
                if (!value.Equals(_date))
                {
                    _date = value;
                    NotifyPropertyChanged("string");
                }
            }
        }
        public string url
        {
            get
            {
                return _url;
            }
            set
            {
                if (!value.Equals(_url))
                {
                    _url = value;
                    NotifyPropertyChanged("url");
                }
            }
        }
        public string name
        {
            get
            {
                return _name;
            }
            set
            {
                if (!value.Equals(_name))
                {
                    _name = value;
                    NotifyPropertyChanged("name");
                }
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
        private void NotifyPropertyChanged(String propertyName)
        {
            PropertyChangedEventHandler handler = PropertyChanged;
            if (null != handler)
            {
              //  App.viewModel.HistoryItems = (App.Current as App).dataHandler.retrieveHistory_DB();
                handler(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

当我启动应用程序的列表得到填充，但我做了一些修改后，在一些枢轴子，并回到主全景视图，我尝试更新OnNavigatedTo中的HistoryItems:

 App.ViewModel.HistoryItems = (App.Current as App).dataHandler.retrieveHistory_DB();

，但列表框没有更新(函数返回正确的数据)。问题是什么呢?History是INotifyPropertyChanged, HistoryItems是ObservableCollection<History>，所以应该没有问题。是什么原因导致列表不更新?