Question

我想将控件的背景颜色设置为按下鼠标左键的时间，然后我希望此控件恢复其正常行为（MouseOver的触发器等）。但是当我在代码隐藏中覆盖属性时，触发器将停止工作。怎么解决？我尝试在MouseUp事件上将属性设置为null，但它无论如何都不起作用。

代码：

private void Item_OnMouseDown(object sender, MouseButtonEventArgs e)
{
    var item = sender as ListBoxItem;
    item.Background = Application.Current.Resources["BlueLightBrush"];
}

以这种方式设置Background之后，它将保持不变，我下次将设置它（触发器不会进行任何更改）

<ControlTemplate.Triggers>
    <Trigger Property="IsMouseOver" Value="True">
        <Setter Property="Background" Value="{StaticResource BlueDarkBrush}"/>
    </Trigger>
    <Trigger Property="IsSelected" Value="True">
        <Setter Property="Background" Value="{StaticResource BlueDarkBrush}"/>
        <Setter Property="BorderBrush" Value="{StaticResource BlueDarkBrush}"/>
    </Trigger>
</ControlTemplate.Triggers>

Answer 1

我设法通过附属财产做我想要的事情：

public static class ListBoxItemAttachedProperties
{
    public static bool GetIsMouseDown(DependencyObject obj)
    {
        return (bool)obj.GetValue(IsMouseDownProperty);
    }

    public static void SetIsMouseDown(DependencyObject obj, bool value)
    {
        obj.SetValue(IsMouseDownProperty, value);
    }

    public static readonly DependencyProperty IsMouseDownProperty =
        DependencyProperty.RegisterAttached("IsMouseDown", typeof(bool), typeof(UIElementAttachedProperties), new PropertyMetadata(false));

}

代码隐藏：

private void Item_OnMouseDown(object sender, MouseButtonEventArgs e)
{
    var listBoxItem = sender as ListBoxItem;
    listBoxItem.SetValue(ListBoxItemAttachedProperties.IsMouseDownProperty, true);
}

private void Item_OnMouseUp(object sender, MouseButtonEventArgs e)
{
    var listBoxItem = sender as ListBoxItem;
    listBoxItem.SetValue(ListBoxItemAttachedProperties.IsMouseDownProperty, false);
}

XAML：

<ControlTemplate.Triggers>
    <Trigger Property="IsMouseOver" Value="True"> 
        <Setter Property="Background" Value="{StaticResource BlueDarkBrush}"/>
    </Trigger>
    <Trigger Property="IsSelected" Value="True">
        <Setter Property="Background" Value="{StaticResource BlueDarkBrush}"/>
        <Setter Property="BorderBrush" Value="{StaticResource BlueDarkBrush}"/>
    </Trigger>
    <Trigger Property="local:ListBoxItemAttachedProperties.IsMouseDown" Value="True">
        <Setter Property="Background" Value="{StaticResource BlueLightBrush}"/>
    </Trigger>
</ControlTemplate.Triggers>

如何以编程方式设置属性后返回触发器？

1 个答案: