c# - WPF 中的 INotifyPropertyChanged

Question

尝试了解 WPF。这是我的测试类:

    public partial class MainWindow : Window, INotifyPropertyChanged
{
    private ObservableCollection<string> _myList = new ObservableCollection<string>();

    public ObservableCollection<string> MyList
    {
        get { return _myList; }
        set
        {
            _myList = value;
            RaisePropertyChanged("_myList");
        }
    }

    public MainWindow()
    {
        InitializeComponent();
        comboBox1.DataContext = _myList;
    }

    private void button1_Click(object sender, RoutedEventArgs e)
    {
        MyList = AnotherClass.SomeMethod();
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void RaisePropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

internal static class AnotherClass
{
    public static ObservableCollection<string> SomeMethod()
    {
        return new ObservableCollection<string> {"this","is","test"};
    }
}

这是 XAML

<Grid>
    <ComboBox Height="23" HorizontalAlignment="Left" Margin="65,51,0,0" Name="comboBox1" VerticalAlignment="Top" Width="120" ItemsSource="{Binding}" />
    <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="310,51,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" />
</Grid>

如何使这段代码起作用？我希望在单击按钮并更新 MyList 后更改 ComboBox 数据。 PropertyChangedEventHandler 始终为空。

Answer 1

问题是您直接将原始列表设置到 Window.DataContext 上，因此没有任何内容会监听 Windows 的 PropertyChanged 事件。

要解决这个问题，请将 DataContext 设置为窗口本身:

this.DataContext = this;

然后更改 Binding 以便引用该属性:

<ComboBox ItemsSource="{Binding MyList}" />

您还需要更改您的属性定义，以便它引发被更改的属性 的名称，而不是成员的名称:

this.RaisePropertyChanged("MyList");