c# - 如何在 WPF 中有条件地执行 EventTrigger？

Question

目前我有以下代码来在值更改时刷新 DataGrid 单元格:

<TextBlock Background="White" Text={Binding Date, NotifyOnTargetUpdated=True} >
    <EventTrigger RoutedEvent="Binding.TargetUpdated" >
        <BeginStoryboard>
            <Storyboard>
                <ColorAnimation AutoReverse="True" From="#1F1F1F" To="#FFFF88" Duration="0:0:0.2" Storyboard.TargetProperty="Background.Color" FillBehavior="Stop" />
            </Storyboard>
        </BeginStoryboard>
    </EventTrigger>
</TextBlock>

现在我只需要在 View 模型的 bool 值为真时执行此动画。我怎样才能做到这一点？

编辑:扩展样本

谢谢。

Answer 1

感谢 XAML 专家在另一个论坛上的回答。这是问题的答案，解决方案是使用以下附加行为:

class AttachedBehaviours
{
    public static bool GetAllowTargetUpdated(DependencyObject obj)
    {
        return (bool)obj.GetValue(AllowTargetUpdatedProperty);
    }

    public static void SetAllowTargetUpdated(DependencyObject obj, bool value)
    {
        obj.SetValue(AllowTargetUpdatedProperty, value);
    }

    // Using a DependencyProperty as the backing store for AllowTargetUpdated.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty AllowTargetUpdatedProperty =
        DependencyProperty.RegisterAttached("AllowTargetUpdated", typeof(bool), typeof(AttachedBehaviours), new UIPropertyMetadata(false, PropChanged));


    static void PropChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
    {
        var ele = obj as FrameworkElement;
        var be = ele.GetBindingExpression(TextBlock.TextProperty);
        if (be == null) return;

        var b = be.ParentBinding;

        var newBinding = new Binding(b.Path.Path);
        newBinding.NotifyOnTargetUpdated = (bool)e.NewValue;

        ele.SetBinding(TextBlock.TextProperty, newBinding);
    }
}

这是它在 XAML 中的用法:

<TextBlock Background="White" Text="{Binding Date}"  local:AttachedBehaviours.AllowTargetUpdated="{Binding EnableAnimations}" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="0,10,0,0"  >