WPF：从父级到子级的绑定列表

Question

我正在尝试将 List<bool> 从 MainWindow 绑定到我的 UserControl。 MainWindow 从其他 UserControl 获取列表。我想将它绑定到它的子控件并在 List 的元素发生更改时执行一些操作，所以我编写了这段代码：

MainWindow 类：

public static readonly DependencyProperty mRowsInfoProperty =
    DependencyProperty.Register("mRowsInfo", typeof(List<bool>), typeof(MainWindow),
        new FrameworkPropertyMetadata(new List<bool>()));

public List<bool> mRowsInfo
{
    get { return (List<bool>)GetValue(mRowsInfoProperty); }
    set { SetValue(mRowsInfoProperty, value); }
}
public List<bool> RowsInfo
{
    get { return mRowsInfo; }
    set
    {
        mRowsInfo = value;
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs("RowsInfo"));
    }
}

MainWindow xaml:

<local:CustomGrid isRowValid="{Binding RowsInfo, Mode=TwoWay}">
<local:ControlButtons ButtonsBacklitList="{Binding mRowsInfo, ElementName=myWindow}"/>

用户控制类：

 public static readonly DependencyProperty ButtonsBacklitListProperty =
            DependencyProperty.Register("ButtonsBacklitList", typeof(ObservableCollection<bool>), typeof(ControlButtons),
                new FrameworkPropertyMetadata(new ObservableCollection<bool>(), onBBLCallBack));

        public ObservableCollection<bool> ButtonsBacklitList
        {

            get { return (ObservableCollection<bool>)GetValue(ButtonsBacklitListProperty); }
            set { SetValue(ButtonsBacklitListProperty, value); }
        }
        private static void onBBLCallBack(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            ControlButtons h = sender as ControlButtons;
            if (h != null)
            {
                h.onBBLChanged();
            }
        }
        protected virtual void onBBLChanged()
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs("ButtonsBacklitList"));
            Console.WriteLine("UPDATED");
        }

当我在代码中的某个点中断时（单击按钮后）ButtonsBacklitList 始终为空。我应该更改或添加什么才能正确执行此操作？

Answer 1

MainWindow 类：

public static readonly DependencyProperty RowsInfoProperty =
    DependencyProperty.Register("RowsInfo", typeof(ObservableCollection<bool>), typeof(MainWindow),
        new FrameworkPropertyMetadata(new ObservableCollection<bool>()));

public ObservableCollection<bool> RowsInfo
{
    get { return (ObservableCollection<bool>)GetValue(RowsInfoProperty); }
    set { SetValue(RowsInfoProperty, value); }
}

主窗口 xaml：

<local:CustomGrid isRowValid="{Binding RowsInfo, Mode=TwoWay}">
<local:ControlButtons ButtonsBacklitList="{Binding RowsInfo, ElementName=myWindow}"/>

用户控件类：

public static readonly DependencyProperty ButtonsBacklitListProperty =
    DependencyProperty.Register("ButtonsBacklitList", typeof(ObservableCollection<bool>), typeof(ControlButtons),
        new FrameworkPropertyMetadata(new ObservableCollection<bool>(), onBBLCallBack));

public ObservableCollection<bool> ButtonsBacklitList
{
    get { return (ObservableCollection<bool>)GetValue(ButtonsBacklitListProperty); }
    set { SetValue(ButtonsBacklitListProperty, value); }
}

// Not sure why you want to capture changes, I hope it's not for binding
// But I'm copying it anyway
private static void onBBLCallBack(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
    ControlButtons h = sender as ControlButtons;
    if (h != null)
    {
        h.onBBLChanged();
    }
}

// This looks super suspicious because all you did is to trigger INotifyPropertyChanged's handler!
// I hope somewhere in your code you actually need to manually handle this change event...
protected virtual void onBBLChanged()
{
    if (PropertyChanged != null)
        PropertyChanged(this, new PropertyChangedEventArgs("ButtonsBacklitList"));
    Console.WriteLine("UPDATED");
}

首先，我感觉您对绑定概念不太熟悉。实现为List<bool> 意味着绑定只会对整个属性引用的变化做出反应（例如this.RowInfo = new List<bool>）。

其次，不知道为什么要将DependencyProperty 与INotifyPropertyChanged 叠加。对于要成为绑定 source 的属性（对于接收更改通知的绑定），它只需要是这两者之一。但是，要使属性成为绑定目标，它必须是DependencyProperty。比如<local:CustomGrid isRowValid="{Binding RowsInfo, Mode=TwoWay}">中，isRowValid是绑定目标，这必须是DependencyProperty，而RowsInfo是绑定源，可以是两者之一。

希望能帮到你。