WPF：绑定列表到列表框控件 [英] WPF: Binding List to ListBox

问题描述

我有一个类：

public class A : INotifyPropertyChanged
{
    public List<B> bList { get; set; } 

    public void AddB(B b)
    {
        bList.Add(b);
        NotifyPropertyChanged("bList");
    }

    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged(string info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }
}

和有约束力的（用户控件的DataContext的是A的一个实例）：

And a binding (DataContext of UserControl is an instance of A):

<ListBox ItemsSource="{Binding Path=bList}" />

元素中显示，不更新列表框后，新的对象被添加到列表

Elements are shown, the ListBox is not updated after new object is added to List

改变列表的ObservableCollection和去除NotifyPropertyChanged处理后的一切工作。

After changing list to ObservableCollection and removing the NotifyPropertyChanged handler everything works.

为什么这个列表不工作？

Why the list is not working?

推荐答案

<击>您的酒店为公共，或绑定引擎将无法访问它。

Your property has to be public, or the binding engine won't be able to access it.

编辑：

改变列表的ObservableCollection和去除NotifyPropertyChanged处理后的一切工作。

After changing list to ObservableCollection and removing the NotifyPropertyChanged handler everything works.

这是precisely为什么的ObservableCollection＆LT; T＆GT;引入类... 的ObservableCollection＆LT; T＆GT; 工具 INotifyCollectionChanged ，这使得当一个项目被添加/删除/替换它来通知用户界面。 列表＆LT; T＆GT; 不会触发任何通知，所以当列表的内容改变了UI无法检测

That's precisely why the ObservableCollection<T> class was introduced... ObservableCollection<T> implements INotifyCollectionChanged, which allows it to notify the UI when an item is added/removed/replaced. List<T> doesn't trigger any notification, so the UI can't detect when the content of the list has changed.

这是你提出的的PropertyChanged 事件不刷新绑定，但随后意识到它的名单，LT的同一个实例的事实; T＆GT; 和以前一样，所以重复使用相同的的ICollectionView 为一体的的的ItemsSource ，内容的ListBox 没有刷新。

The fact that you raise the PropertyChanged event does refresh the binding, but then it realizes that it's the same instance of List<T> as before, so it reuses the same ICollectionView as the ItemsSource, and the content of the ListBox isn't refreshed.

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