Route/Tunnel 属性值到另一个属性行为

Question

我有一个 DataGrid 并想将 AlternationIndex 传递给绑定元素（离开当前对象）。

单元格模板

<DataGridTemplateColumn.CellTemplate>
    <DataTemplate>
        <Grid>
            <TextBlock HorizontalAlignment="Center" Text="{Binding Index}"/>
            <i:Interaction.Behaviors>
                <behaviors:RoutePropertyValue 
                    Source="{Binding RelativeSource={RelativeSource AncestorType=DataGridRow}, Path=(ItemsControl.AlternationIndex)}"
                    Target="{Binding Index, Mode=TwoWay}"/>
            </i:Interaction.Behaviors>
        </Grid>
    </DataTemplate>
</DataGridTemplateColumn.CellTemplate>

*RoutePropertyValueBehavior**

public class RoutePropertyValue : Behavior<FrameworkElement>
{
    /// <summary>
    /// The source property value
    /// </summary>
    public object Source
    {
        get => (object)GetValue(SourceProperty);
        set => SetValue(SourceProperty, value);
    }

    /// <summary>
    /// The <see cref="Source"/> DependencyProperty.
    /// </summary>
    public static readonly DependencyProperty SourceProperty = DependencyProperty.Register("Source", typeof(object), typeof(RoutePropertyValue), new PropertyMetadata(null, SourceChangedCallback));

    private static void SourceChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs args)
    {
        if (d is RoutePropertyValue instance)
        {
            instance.OnSourceChanged();
        }
    }

    protected virtual void OnSourceChanged()
    {
        Target = Source;
    }


    /// <summary>
    /// The target where the value should be writetn
    /// </summary>
    public object Target
    {
        get => (object)GetValue(TargetProperty);
        set => SetValue(TargetProperty, value);
    }

    /// <summary>
    /// The <see cref="Target"/> DependencyProperty.
    /// </summary>
    public static readonly DependencyProperty TargetProperty = DependencyProperty.Register("Target", typeof(object), typeof(RoutePropertyValue), new PropertyMetadata(null));

}

实际上调试时Target总是null。此外，如果更改 DataGrid 内的顺序，则不会再次调用 SourceChangedCallback。所以无论如何，将 'tunnel' 属性值转换为另一个属性.

的方法似乎是错误的

Answer 1

您可以绑定到目标对象，然后指定要设置的源属性。每当设置任何目标属性时，您都应该尝试设置源属性。试试这个：

public class RoutePropertyValue : Behavior<FrameworkElement>
{
    public object Source
    {
        get => GetValue(SourceProperty);
        set => SetValue(SourceProperty, value);
    }

    public static readonly DependencyProperty SourceProperty = DependencyProperty.Register(nameof(Source), typeof(object), 
        typeof(RoutePropertyValue), new PropertyMetadata(null, Callback));

    private static void Callback(DependencyObject d, DependencyPropertyChangedEventArgs args)
    {
        if (d is RoutePropertyValue instance)
            instance.OnAnyValueChanged();
    }

    protected virtual void OnAnyValueChanged()
    {
        if (!string.IsNullOrEmpty(TargetMember))
            TargetObject?.GetType().GetProperty(TargetMember)?.SetValue(TargetObject, Source);
    }

    public object TargetObject
    {
        get => GetValue(TargetObjectProperty);
        set => SetValue(TargetObjectProperty, value);
    }

    public static readonly DependencyProperty TargetObjectProperty = DependencyProperty.Register(nameof(TargetObject), typeof(object), 
        typeof(RoutePropertyValue), new PropertyMetadata(null, Callback));

    public string TargetMember
    {
        get => (string)GetValue(TargetMemberProperty);
        set => SetValue(TargetMemberProperty, value);
    }

    public static readonly DependencyProperty TargetMemberProperty = DependencyProperty.Register(nameof(TargetMember), typeof(string),
        typeof(RoutePropertyValue), new PropertyMetadata(null, Callback));
}

XAML:

<behaviors:RoutePropertyValue 
    TargetObject="{Binding}"
    TargetMember="Index"
    Source="{Binding RelativeSource={RelativeSource AncestorType=DataGridRow}, Path=(ItemsControl.AlternationIndex)}"
    />

Route/Tunnel 属性值到另一个属性行为

Route/Tunnel property value to another property with a behavior

wpf

behavior

Route/Tunnel 属性 值到另一个 属性 行为

Route/Tunnel property value to another property with a behavior

wpf

behavior

Route/Tunnel 属性值到另一个属性行为