删除 ObservableCollection 项

Question

我创建了一个 ObservableCollection 并将其绑定到我的 Listview。在我的项目加载到 ListView 之前，它们正在使用 Linq 进行排序，然后 然后 添加到 ListView：

//Get's the Items and sets it
public ObservableCollection<ItemProperties> ItemCollection { get; private set; }

//Orders the Items alphabetically using the Title property
DataContext = ItemCollection.OrderBy(x => x.Title);

<!--ItemCollection has been binded to the ListView-->
<ListView ItemsSource="{Binding}"/>

我遇到的问题是我无法从集合中删除选定的项目。仅当我添加DataContext = ItemCollection.OrderBy(x => x.Title); 时才会出现此问题。如果是DataContext = ItemCollection，那么我可以删除选中的项目。

一旦打开 ContextMenu (MenuFlyout) 并单击“删除”项，我的删除方法就会被激活。我的删除方法是：

private void btn_Delete_Click(object sender, RoutedEventArgs e)
{
   var edit_FlyOut = sender as MenuFlyoutItem;
   var itemProperties = edit_FlyOut.DataContext as ItemProperties;
   ItemCollection.Remove(itemProperties);
}

这是我的 ItemProperties 类：

public class ItemProperties : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    public ItemProperties() { }
    private string m_Title;
    public string Title
    {
        get { return m_Title; }
        set
        {
            m_Title = value;
            OnPropertyChanged("Title");
        }
    }
    private string m_Post;
    public string Post
    {
        get { return m_Post; }
        set
        {
            m_Post = value;
            OnPropertyChanged("Post");
        }
    }
    private string m_Modified;
    public string Modified
    {
        get { return m_Modified; }
        set
        {
            m_Modified = value;
            OnPropertyChanged("Modified");
        }
    }
    private string m_ID;
    public string ID
    {
        get { return m_ID; }
        set
        {
            m_ID = value;
            OnPropertyChanged("ID");
        }
    }

    protected void OnPropertyChanged(string name)
    {
        PropertyChangedEventHandler handler = this.PropertyChanged;
        if (handler != null)
            handler(this, new PropertyChangedEventArgs(name));
    }
}

编辑

我如何加载我的项目：

public async void GetList()
 {
    var AppStorage = ApplicationData.Current.LocalFolder;
    var noteFolders = await AppStorage.GetFolderAsync(@"folder\files\");
    var Folders = await noteFolders.GetFoldersAsync();

    ItemCollection = new ObservableCollection<ItemProperties>();
    foreach (var noteFolder in Folders)
      {

         ItemCollection.Add(new ItemProperties { Title = readTitle, Post = readBody, ID = noteFolder.Name, Modified = timeFormat });
      }
      //code which readers and adds text to the properties...
      DataContext = ItemCollection.OrderBy(x => x.Title);
}

Answer 1

您可以从 ListView 中获取选定的项目并将其删除：

if (lvElement.SelectedIndex == -1) return;
ItemProperties selectedProperty = (ItemProperties)lvElement.SelectedItem;

// remove selectedProperty from original collection

Answer 2

我的解决办法是：

ItemCollection = new ObservableCollection<ItemProperties>(ItemCollection.OrderBy(a => a.Title));
DataContext = ItemCollection;

似乎我必须将 ItemCollection 重新初始化为新的 ObservableCollection 并一次性订购，而不是加载项目然后排序。这样做是它有一个列表，首先添加项目，然后是另一个必须排序的列表。为了避免这种情况，我不得不一口气完成所有工作。以上帮助了我。我是从here 那里得到的。