如何使用数据触发器设置WPF行为属性

Question

我试图通过以下方式使用样式设置WPF行为属性：

<StackPanel>
    <CheckBox Name="IsFemaleChkBox" Content="Is Female ?" />
    <TextBlock>
        <Hyperlink> <!--setting property directly like this:  local:MyHyperLinkBehavior.Salutation="Mr." isn't working either-->
            <TextBlock Text="My Hyperlink"/>
            <Hyperlink.Style>
                <Style TargetType="Hyperlink">
                    <Setter Property="local:MyHyperLinkBehavior.Salutation" Value="Mr." />
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding IsChecked, ElementName=IsFemaleChkBox}" Value="True">
                            <Setter Property="local:MyHyperLinkBehavior.Salutation" Value="Miss" />
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </Hyperlink.Style>
        </Hyperlink>
    </TextBlock>
</StackPanel>

行为类代码是这样的：

class MyHyperLinkBehavior : Behavior<Hyperlink>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.Click += AssociatedObject_Click;
    }

    public static bool GetIsFemale(DependencyObject obj)
    {
        return (bool)obj.GetValue(IsFemaleProperty);
    }

    public static void SetIsFemale(DependencyObject obj, bool value)
    {
        obj.SetValue(IsFemaleProperty, value);
    }

    // Using a DependencyProperty as the backing store for IsFemale.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty IsFemaleProperty =
        DependencyProperty.RegisterAttached("IsFemale", typeof(bool), typeof(MyHyperLinkBehavior), new PropertyMetadata(false));


    public static string GetSalutation(DependencyObject obj)
    {
        return (string)obj.GetValue(SalutationProperty);
    }

    public static void SetSalutation(DependencyObject obj, string value)
    {
        obj.SetValue(SalutationProperty, value);
    }

    // Using a DependencyProperty as the backing store for Salutation.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty SalutationProperty =
        DependencyProperty.RegisterAttached("Salutation", typeof(string), typeof(MyHyperLinkBehavior), new PropertyMetadata(default(string)));

    void AssociatedObject_Click(object sender, System.Windows.RoutedEventArgs e)
    {
        MessageBox.Show(Convert.ToString(GetValue(SalutationProperty)));
    }
}

我无法弄清楚为什么这不起作用。 或者使用样式设置行为的属性根本无效？ 如果这是无效的，那么反过来是什么。

Answer 1

WPF中有两种类型的行为 ：

1. System.Windows.Interactivity行为，也称为混合行为

   这些行为是从System.Windows.Interactivity.Behavior继承的类，您可以通过添加到使用它们来添加到Behaviors集合来使用它们，例如：

    <Rectangle> <i:Interaction.Behaviors> <ei:MouseDragElementBehavior /> </i:Interaction.Behaviors> </Rectangle> 

   请注意，这些行为没有任何自定义附加属性。 自动调用OnAttached和OnDetached方法。

   • 优点 ：易于实施
   • 缺点 ：不适用于样式（但是，它适用于ControlTemplates和DataTemplates）

2. 作为自定义附加属性实现的行为

   在这些行为中，自定义附加属性的PropertyChangedCallback中定义了逻辑。

    public static readonly DependencyProperty SalutationProperty = DependencyProperty.RegisterAttached("Salutation", typeof(string), typeof(MyHyperLinkBehavior), new PropertyMetadata(OnSalutationPropertyChanged)); private static void OnSalutationPropertyChanged(object sender, DependencyPropertyChangedEventArgs e) { //attach to event handlers (Click, Loaded, etc...) } 

   • 优点 ：可以定义样式，更易于使用
   • 缺点 ：很好的代码，实现起来有点困难

您将这两种行为混合在一起。 选择一个并使用它！ 由于您希望在样式中使用它，因此您应选择实现为自定义附加属性的行为

Answer 2

我得到了它的工作 ，这是我的一个小小想念。

1. 我忘了在超链接上设置行为。
2. 我需要获取attachObject的属性而不是
   行为。

以下代码工作正常：

<StackPanel>
    <CheckBox Name="IsFemaleChkBox" Content="Is Female ?" />
    <TextBlock>
        <Hyperlink>
            <TextBlock Text="My Hyperlink"/>
            <i:Interaction.Behaviors> <!--Missed setting behavior-->
                <local:MyHyperLinkBehavior />
            </i:Interaction.Behaviors>
            <Hyperlink.Style>
                <Style TargetType="Hyperlink">
                    <Setter Property="local:MyHyperLinkBehavior.Salutation" Value="Mr." />
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding IsChecked, ElementName=IsFemaleChkBox}" Value="True">
                            <Setter Property="local:MyHyperLinkBehavior.Salutation" Value="Miss" />
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </Hyperlink.Style>
        </Hyperlink>
    </TextBlock>
</StackPanel>

而行为：

class MyHyperLinkBehavior : Behavior<Hyperlink>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.Click += AssociatedObject_Click;
    }

    public static bool GetIsFemale(DependencyObject obj)
    {
        return (bool)obj.GetValue(IsFemaleProperty);
    }

    public static void SetIsFemale(DependencyObject obj, bool value)
    {
        obj.SetValue(IsFemaleProperty, value);
    }

    // Using a DependencyProperty as the backing store for IsFemale.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty IsFemaleProperty =
        DependencyProperty.RegisterAttached("IsFemale", typeof(bool), typeof(MyHyperLinkBehavior), new PropertyMetadata(false));


    public static string GetSalutation(DependencyObject obj)
    {
        return (string)obj.GetValue(SalutationProperty);
    }

    public static void SetSalutation(DependencyObject obj, string value)
    {
        obj.SetValue(SalutationProperty, value);
    }

    // Using a DependencyProperty as the backing store for Salutation.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty SalutationProperty =
        DependencyProperty.RegisterAttached("Salutation", typeof(string), typeof(MyHyperLinkBehavior), new PropertyMetadata(default(string)));

    void AssociatedObject_Click(object sender, System.Windows.RoutedEventArgs e)
    {
        // Changing "GetValue(SalutationProperty)" to "this.AssociatedObject.GetValue(SalutationProperty)" works
        MessageBox.Show(Convert.ToString(this.AssociatedObject.GetValue(SalutationProperty)));
    }
}