如何从Windows Phone 8 App C＃的列表中删除项目

Question

When the user taps on the particular item in the list new page opens and there he can see full details of the particular item. He can delete particular item if he thinks he don't want that. My problem is the file was not deleting from the list.

public partial class DetailsPage : PhoneApplicationPage
{
    SavedData prkdata = new SavedData();
    SavedDataList parkinglistobj = new SavedDataList();
    IsolatedStorageFile Settings = IsolatedStorageFile.GetUserStoreForApplication();
    int index;

    public DetailsPage()
    {
        InitializeComponent();        
        //this.Loaded += MainPage_Loaded;
    }        

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {              
         string selectedIndex = "";

        if (NavigationContext.QueryString.TryGetValue("selectedItem", out selectedIndex))
         {
             index = int.Parse(selectedIndex);
             try
             {
                 parkinglistobj.Clear();

                 if (Settings.FileExists("CardItemList"))
                 {
                     using (IsolatedStorageFileStream fileStream = Settings.OpenFile("CardItemList", FileMode.Open))
                     {
                         DataContractSerializer serializer = new DataContractSerializer(typeof(SavedDataList));
                         parkinglistobj = (SavedDataList)serializer.ReadObject(fileStream);
                     }
                 }

                 ParkListBox.ItemsSource = parkinglistobj.Where(i => i.ID == index).ToList();

                 //String itemselected = parkinglistobj.Where(i => i.ID == index).Select(i.CardName).ToString();
                 //MessageBox.Show(itemselected);
             }
             catch
             {
                 //
             }
         }
    }

    private void DeleteFile(object sender, EventArgs e)
    {
        //ParkListBox.SelectedItem = parkinglistobj.Select(i => i.ID == index);
        //SavedData item = ParkListBox.DataContext as SavedData;
        SavedData item = parkinglistobj.Select(i => i.ID == index) as SavedData;
        //SavedData item = ParkListBox.SelectedItem as SavedData;
        parkinglistobj.Remove(item);
        MessageBox.Show("Deleted Successfully");
    }
}

Answer 1

在DeleteFile事件处理程序中，您应该删除该项目，然后将其重新序列化回CardItemList文件。

Answer 2

You to need to communicate back to your View (which is your ListBox ) that something has changed so it needs to update/redraw its Content.

Unforunately, a generic List<T> will not automatically do this for you. What you need is to use an ObservableCollection<T> instead.

MSDN: ObservableCollection Class , pay attention to this part of the description:

Represents a dynamic data collection that provides notifications when items get added, removed, or when the whole list is refreshed.

If you used it correctly any addition and deletion to the collection will result in the ListBox redrawing itself.