Question

我的窗口使用MyUserControl并通过MyItemsProperty属性向其传递一组项目。 MyUserControl会将项目转换为MyClassBag，并将项目添加到WrappedItems集合（OnMyItemsChanged-＆gt; CollectionChanged-＆gt; AddItem），该集合绑定到DataGrid的ItemsSource。

问题是ItemsSource没有更新（我在control.WrappedItems.Add(new MyClassBag { ... });设置制动点，它确实到了那里）。
但是，如果我在MyUserControl内放置一个按钮并通过按钮的click方法添加项目（WrappedItems.Add(new MyClassBag { ... });），则ItemsSource会更新。有什么问题？

public partial class MyUserControl : UserControl
{
    public static readonly DependencyProperty MyItemsProperty =             
      DependencyProperty.Register("MyItems",
         typeof(ObservableCollection<MyClass>), 
         typeof(MyUserControl),
         new PropertyMetadata(
            new ObservableCollection<MyClass>(),
            new PropertyChangedCallback(OnMyItemsChanged)
         )
      );

    public ObservableCollection<MyClass> MyItems
    {
        get { return (ObservableCollection<MyItems>)GetValue(MyItemsProperty); }
        set { SetValue(MyItemsProperty, value); }
    }

    private static void OnMyItemsChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        control = d as MyUserControl;
        var items = e.NewValue as ObservableCollection<MyClass>;

        states.CollectionChanged += new NotifyCollectionChangedEventHandler(CollectionChanged);
        AddItem(control, items);
    }

    private static void CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
        var items = sender as ObservableCollection<MyClass>;

        if (e.Action == NotifyCollectionChangedAction.Add)
        {
            control.AddNewItem();
        }
    }

    public ObservableCollection<MyClassBag> WrappedItems { get; set; }

    public void AddNewItem()
    {
        WrappedItems.Add(new MyClassBag { ... });
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        AddNewItem();
    }
}

MyUserControl.XAML

<DataGrid ItemsSource="{Binding WrappedItems ... />
<Button Click="Button_Click" />

Window.cs

public partial class Window1 : Window
{
    public ObservableCollection<MyClass> ItemsForMyUserControl { get; set; }

    private void Load()
    {
         ItemsForMyUserControl.Add(new MyClass(...));
         ItemsForMyUserControl.Add(new MyClass(...));
    }
}

Window.xaml

<uc:MyUserControl MyItems="{Binding ItemsForMyUserControl}" />

Answer 1

前段时间我遇到过类似的问题。

请让MyClass类继承自Freezable类，一切都可行。如果有帮助，请告诉我。

为什么ItemsSource没有在DataGrid中更新

1 个答案: