可观察的集合添加对象不刷新视图

Question

这是我的代码，当我按下与 Clicked 属性 addische 绑定的按钮时，新项目被添加到 ListView 但我在列表中看不到它。

public partial class GS : ContentPage
{
    private GSViewModel _viewModel;

    public GS()
    {
        InitializeComponent();
        BindingContext = _viewModel = new GSViewModel();
    }

    private void addische(object sender, EventArgs e)
    {
        _viewModel.newItemAdded();
    }

    public class GSViewModel : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        public ObservableCollection<schItem> _scheListItem;
        public ObservableCollection<schItem> Items { get { return _scheListItem; }
            private set
            {
                if (_scheListItem != value)
                {
                    _scheListItem = value;
                    OnPropertyChanged();
                }
            }
        }

        public void newItemAdded()
        {
            Items.Add(new schItem
            {
                realm_id = 133,
                list_id = 33
            });
        }

        public GSViewModel()
        {
            Items = new ObservableCollection<schItem>();
            initListView();
        }

        public void initListView()
        {
           //get data
        }

        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public class schItem
    {
        public int realm_id { get; set; }
        public int list_id { get; set; }
        }
    }

也许我错过了 INotifyPropertyChanged 类的东西。

我正在 Android 设备中调试

Answer 1

您可能看不到任何东西的几个原因。

1. 你的绑定是错误的，所以你不会看到任何文字。修复更改

         <Label Text = "{Binding name}" HeightRequest="20" FontAttributes="Bold"/>
         <Label Text = "{Binding data, StringFormat='a {0:F0}'}" />
   

到

      <Label Text = "{Binding realm_id}" HeightRequest="20" FontAttributes="Bold"/>
      <Label Text = "{Binding list_id}" />

1. 检查“delete.png”是否存在于正确的位置，而不是“delete.jpg”

2. 修复后删除 ListView IsEnabled="False"