Question

假设我在WPF UserControl中有以下代码。我想绑定到Asset.ChildProperty。它目前不起作用，因为我在Asset属性更改时没有收到通知。我如何安排事情，以便在AssetID更改时触发Asset属性？

public static readonly DependencyProperty AssetIdProperty = DependencyProperty.Register("AssetId", typeof(string), typeof(GaugeBaseControl));

[Browsable(false), DataMember]
public string AssetId
{
    get { return (string)GetValue(AssetIdProperty); }
    set { SetValue(AssetIdProperty, value); }
}

[DisplayName("Asset Item"), Category("Value Binding")]
public AssetViewModel Asset
{
    get { return Manager.Models.FirstOrDefault(m => m.Model.UniqueId == AssetId); }
    set
    {
        if (value == null)
            AssetId = string.Empty;
        else
            AssetId = value.Model.UniqueId;
    }
}

Answer 1

当PropertyMetadata的值更改并从该回调方法引发DependencyProperty事件时，您可以在DependencyProperty的{{1}}中指定一个回调方法

PropertyChanged

如果你从public class MyClass : DependencyObject, INotifyPropertyChanged { public MyClass () { } public event PropertyChangedEventHandler PropertyChanged; public bool State { get { return (bool)this.GetValue(StateProperty); } set { this.SetValue(StateProperty, value); } } public static readonly DependencyProperty StateProperty = DependencyProperty.Register( "State", typeof(bool), typeof(MyClass), new PropertyMetadata( false, // Default value new PropertyChangedCallback(OnDependencyPropertyChange))); private static void OnDependencyPropertyChange( DependencyObject d, DependencyPropertyChangedEventArgs e) { if (this.PropertyChanged != null) { this.PropertyChanged(d, new PropertyChangedEventArgs(e.Property.Name); } } }属性的setter中引发PropertyChanged个事件，那么当绑定属性时它们不会触发，因为绑定会直接调用State，而不是StateProperty。

Answer 2

实施INotifyPropertyChanged并在PropertyChanged更改时（在setter方法中）提升Asset事件。

WPF中的依赖属性 - 如何绑定它？

2 个答案: