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如何(如果有的话)从Style Trigger IsSelected属性调用VisualStateManager.GotToState

visualstatemanager triggers xaml wpf

0

cpdev · 技术社区 · 2 年前

我有VisualStateManager.VisualStateGroups定义如下:

            <VisualStateManager.VisualStateGroups>
            <VisualStateGroup x:Name="PopupStates">
                <VisualState x:Name="PopupClosed">
                    <Storyboard>
                        <BooleanAnimationUsingKeyFrames Storyboard.TargetName="ContextPopup"
                                            Storyboard.TargetProperty="IsOpen">
                            <DiscreteBooleanKeyFrame KeyTime="0:0:0.25"
                                       Value="False" />
                        </BooleanAnimationUsingKeyFrames>
                        <ObjectAnimationUsingKeyFrames
                                        Storyboard.TargetName="rootGrid"
                                        Storyboard.TargetProperty="(Panel.Background)">
                            <DiscreteObjectKeyFrame KeyTime="0:0:0.25" Value="{DynamicResource BrushIconComboBox_Popup_Closed_Background}" />
                        </ObjectAnimationUsingKeyFrames>
                    </Storyboard>
                </VisualState>
                <VisualState x:Name="PopupOpen">
                    <Storyboard>
                        <BooleanAnimationUsingKeyFrames Storyboard.TargetName="ContextPopup"
                                            Storyboard.TargetProperty="IsOpen">
                            <DiscreteBooleanKeyFrame KeyTime="0:0:0.25"
                                       Value="True" />
                        </BooleanAnimationUsingKeyFrames>
                        <ObjectAnimationUsingKeyFrames
                                        Storyboard.TargetName="rootGrid"
                                        Storyboard.TargetProperty="(Panel.Background)">
                            <DiscreteObjectKeyFrame KeyTime="0:0:0.25" Value="{DynamicResource BrushIconComboBox_Popup_Open_Background}" />
                        </ObjectAnimationUsingKeyFrames>
                    </Storyboard>
                </VisualState>
            </VisualStateGroup>
        </VisualStateManager.VisualStateGroups>

在Style声明中,如果单击列表框项(即通过鼠标操作选择),我想调用VisualStateManager.GoToState“PopupClosed”。我找不到VisualStateManager.GoToState可以与触发器组合的示例,例如:

     <Style.Triggers>
        <Trigger Property="IsSelected" Value="true">
           ... VisualStateManager.GoToState declaration ....
        </Trigger>
    </Style.Triggers>

有办法做到这一点吗?感谢您的帮助。

0 回复 | 直到 2 年前

1

0

BionicCode 2 年前

不能从XAML调用方法,除非这些方法是事件/命令处理程序(委托)。必须从非XAML上下文显式调用方法。

VisualStates 通常由定义它们的控件处理。如果这与自定义控件无关,并且您需要更改视觉状态转换行为或触发器,那么最干净的方法是扩展相关控件以私下实现状态转换。
但是,使用 VisualStateManager.GoToElementState 允许从外部将控件转换为可视状态,例如从附加的 ListBoxItem.Selected 事件处理程序。。

<ListBox>
  <ListBox.ItemContainerStyle>
    <Style TargetType="ListBoxItem">
      <EventSetter Event="Selected"
                   Handler="ListBoxItem_Selected" />
    </Style>
  </ListBox.ItemContainerStyle>
</ListBox>

private void ListBoxItem_Selected(object sender, RoutedEventArgs e)
{
  var listBoxItem = sender as ListBoxItem;
  var templateChildThatDefinesVisualStateGroups = VisualTreeHelper.GetChild(listBoxItem, 0) as FrameworkElement;
  _ = VisualStateManager.GoToElementState(templateChildThatDefinesVisualStateGroupshild, "PopupClosed", true);
}