C#WPF - 在 add/remove 上绑定更新但不在更新上绑定

Question

在我的 WPF 应用程序中，我有一个带有编辑、添加和删除按钮的 ListView。按删除或添加按钮，立即在 GUI 中显示更改。

按下“更新”按钮，不会更改 GUI，只有当我切换到另一个页面（使用 IPage）并返回时，才会显示该页面 refreshed/the 更改。

我也希望在更新位置的属性 Naam 时刷新视图。

Xaml:

<ListView ItemsSource="{Binding Locations, Mode=TwoWay}" SelectedItem="{Binding SelectedLocation, Mode=TwoWay}">
    <ListView.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Naam}"></TextBlock>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>
<Button Content="Update" Command="{Binding UpdateLocationCommand}" />
<Button Content="Remove" Command="{Binding RemoveLocationCommand}" />
<Button Content="Add" Command="{Binding AddLocationCommand}" />

虚拟机：

class ClassName : ObservableObject, IPage, INotifyPropertyChanged
{
    private ObservableCollection<LocatieModel> _locations = new ObservableCollection<LocatieModel>();
    public ObservableCollection<LocatieModel> Locations
    {
       get { return _locations; }
       set
       {
           _locations = value;
           OnPropertyChange("Locaties");
       }
    }
    private LocatieModel selectedLocation;
    public LocatieModel SelectedLocation
    {
        get { return selectedLocation; }
        set
        {
            selectedLocation= value;
            OnPropertyChange("SelectedLocation");
        }
    }


    public VM()
    {
        addLocationCommand = new Command(AddLocation, true);
        updateLocationCommand = new Command(UpdateLocation, true);
        removeLocationCommand = new Command(RemoveLocation, true);
    }

    private void AddLocation(object obj)
    {
        Locations.Add(new LocatieModel() { Naam = "banana1"});
    }

    private void RemoveLocation(object obj)
    {
        Locations.Remove(SelectedLocation);
    }

    private void UpdateLocation(object obj)
    {
        Locations.Single(l => l == SelectedLocation).Naam = "apple42";
    }


    // Part for InotificationChanged
   public event PropertyChangedEventHandler PropertyChanged;
   private void OnPropertyChange(string propertyname)
   {
       PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyname));
   }
}

而 LocatieModel 只是一个模型：

public class LocatieModel 
{
   public int Id { get; set; }
   public string Naam { get; set; }
}

如何让gui在更新时更新列表？可以自动触发吗？没主意了。谢谢你的时间。

PS：我查看了 possible answer，但这使它成为一个不可见（不存在）元素的列表。

编辑：我昨天尝试在 LocatieModel class 中实施 INotifyPropertyChanged 但没有成功。可能是某个地方的疏忽，因为现在它起作用了。谢谢:)

Answer 1

要更新 Naam，您必须在 LocatieModel class.

中实施 INotifyPropertyChanged

LocatieModel 到

public class LocatieModel : INotifyPropertyChanged
{
   public int Id { get; set; }

   private string naam;

   public string Naam 
   {
      get { return naam; }
      set
      {
          naam = value;
          OnPropertyChange(nameof(Naam));
      }
   }

   public event PropertyChangedEventHandler PropertyChanged;

   protected void OnPropertyChange(string propertyName)
   {
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
   }
}

C#WPF - 在 add/remove 上绑定更新但不在更新上绑定

C#WPF - Binding updates on add/remove but not on update

data-binding

wpf

mvvm