c# - x :bind UI not update when PropertyChanged in UWP

Question

我正在使用 x:Bind 和 INotifyPropertyChanged 更新 UWP 应用程序中的 UI。但它的行为类似于 OneTime 绑定(bind)，即使我将其设置为 OneWay。

Bindings.Update() 有效，但我想知道为什么 INotifyPropertyChanged 失败。

XAML

<TextBlock Text="{x:Bind staffVM.Name, Mode=OneWay}"/>

隐藏代码:

private StaffViewModel staffVM;
private void ListView_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    // I want to change staffVM according to ListView's selection.
    staffVM = staffListView.SelectedItem as StaffViewModel;
    staffVM.Update(); // If change this to Bindings.Update(), It works.
}

View 模型:

public class StaffViewModel: INotifyPropertyChanged
{
    private Character character;
    public string Name => character.name == string.Empty ? null : character.name;
    public void Update()
    {
        RaisePropertyChanged(string.Empty);
    }

    public event PropertyChangedEventHandler PropertyChanged;

    public void RaisePropertyChanged([CallerMemberName]string propName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propName));
    }
}

Answer 1

首先，您需要指定要更新的变量的名称:

public void Update()
{
    RaisePropertyChanged(nameof(Name));
}

文档和示例:https://learn.microsoft.com/en-us/uwp/api/windows.ui.xaml.data.inotifypropertychanged.propertychanged

其次，默认情况下x:Bind是OneTime要修复此问题，请添加 Mode="OneWay"

Mode Specifies the binding mode, as one of these strings: "OneTime", "OneWay", or "TwoWay". The default is "OneTime". Note that this differs from the default for {Binding}, which is "OneWay" in most cases.

请阅读文档 https://learn.microsoft.com/en-us/windows/uwp/xaml-platform/x-bind-markup-extension