Question

我遇到了一个我无法解决的问题。我希望在这里找到答案。当选择某个listboxitem时，我需要一个列表框来隐藏一半。我设置了一个带有不透明蒙版动画的故事板，它在混合中运行良好。我的问题我无法启动BeginStoryboard。我尝试了很多方法而没有成功。我需要隐藏列表框以显示其背后的内容。我从XML数据文件中生成listboxitems，并基于我计划启动故事板播放的名称节点。

这就是我所拥有的。我创建了我在ListBoxItem样式中设置的DataTemplate：

<DataTemplate x:Key="SelectedListBoxItemDataTemplate">
        <StackPanel x:Name="DataItemSelected" Orientation="Horizontal" Margin="12,0,0,0" >
                <TextBlock FontFamily="Arial" Text="►" VerticalAlignment="Center" HorizontalAlignment="Center" Visibility="{Binding XPath=state}" Margin="-4, 0,6,4"/>
                <Image x:Name="ListBoxImage" Source="{Binding XPath=icon}" Margin="4,4,14,4" VerticalAlignment="Center" HorizontalAlignment="Center" Stretch="Uniform" />
                <TextBlock x:Name="textBlock" Text="{Binding XPath=name}" LineHeight="22" Foreground="#FFFFFFFF" FontSize="16"  />  
                <Border x:Name="PART_Icon" Background="{x:Null}" Width="{Binding NodeValue.Width}" HorizontalAlignment="Left" Padding="3,0"></Border>
            </StackPanel>

        <DataTemplate.Triggers>
            <DataTrigger Binding="{Binding XPath=name}" Value="SERVERS">
                <Setter TargetName="PART_Icon" Property="Background" Value="Black" />
                <DataTrigger.EnterActions>
                    <BeginStoryboard Storyboard="{StaticResource HideListBox}" x:Name="HideListBox_BeginStoryboard"/>
                </DataTrigger.EnterActions>  
            </DataTrigger>
        </DataTemplate.Triggers>
    </DataTemplate>

我需要运行这个故事板，我保存在Window.Resources：

<Storyboard x:Key="HideListBox">
        <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.OpacityMask).(GradientBrush.GradientStops)[0].(GradientStop.Offset)" Storyboard.TargetName="Nav_ListBox">
            <EasingDoubleKeyFrame KeyTime="0" Value="0.069"/>
            <EasingDoubleKeyFrame KeyTime="0:0:0.4" Value="1"/>
        </DoubleAnimationUsingKeyFrames>
        <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.OpacityMask).(GradientBrush.GradientStops)[1].(GradientStop.Offset)" Storyboard.TargetName="Nav_ListBox">
            <EasingDoubleKeyFrame KeyTime="0" Value="0.069"/>
            <EasingDoubleKeyFrame KeyTime="0:0:0.4" Value="1"/>
        </DoubleAnimationUsingKeyFrames>
        <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.OpacityMask).(GradientBrush.GradientStops)[1].(GradientStop.Color)" Storyboard.TargetName="Nav_ListBox">
            <EasingColorKeyFrame KeyTime="0" Value="White"/>
            <EasingColorKeyFrame KeyTime="0:0:0.4" Value="White"/>
        </ColorAnimationUsingKeyFrames>
        <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.OpacityMask).(GradientBrush.GradientStops)[0].(GradientStop.Color)" Storyboard.TargetName="Nav_ListBox">
            <EasingColorKeyFrame KeyTime="0" Value="#00000000"/>
            <EasingColorKeyFrame KeyTime="0:0:0.4" Value="#00000000"/>
        </ColorAnimationUsingKeyFrames>
        <PointAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.OpacityMask).(LinearGradientBrush.StartPoint)" Storyboard.TargetName="Nav_ListBox">
            <EasingPointKeyFrame KeyTime="0" Value="1.076,0.501"/>
            <EasingPointKeyFrame KeyTime="0:0:0.4" Value="1,0.5"/>
        </PointAnimationUsingKeyFrames>
        <PointAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.OpacityMask).(LinearGradientBrush.EndPoint)" Storyboard.TargetName="Nav_ListBox">
            <EasingPointKeyFrame KeyTime="0" Value="0.035,0.501"/>
            <EasingPointKeyFrame KeyTime="0:0:0.4" Value="0.2,0.5"/>
        </PointAnimationUsingKeyFrames>
    </Storyboard>

我收到“Nav_ListBox”对象无法找到的错误。我知道列表框对象不能从datatemplate级别获得。我想知道什么是正确的解决方案，以启用动画播放和最终删除点击其他listboxitem。提前谢谢。

Answer 1

我快速整理了一些东西，希望能帮助你（新的默认WPF应用程序，MainWindow的DataContext设置为自己）。我最终使用IValueConverter从ListBox的SelectedItem中获取生成的XmlLinkedNode中的Name，但是应该有一种更优雅的方式使用我不熟悉的XPath语句。基本上在ListBoxes样式上声明你的Storyboard，而不是在Datatemplate：

XAML：

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApplication1"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <XmlDataProvider x:Key="persons"
                         XPath="persons/person"
                         Source="xmldata.xml" />
        <local:SelectionConverter x:Key="selectionConverter" />
    </Window.Resources>

    <Grid>
        <ListBox Background="White" ItemsSource="{Binding Source={StaticResource persons}}" x:Name="lst">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding XPath=name}" />
                        <TextBlock Text="{Binding XPath=prop}" />
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
            <ListBox.Style>
                <Style>
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding ElementName=lst, Path=SelectedItem, Converter={StaticResource selectionConverter}}"
                                     Value="b">
                            <DataTrigger.EnterActions>
                                <BeginStoryboard>
                                    <Storyboard Duration="0:0:1">
                                        <ColorAnimation Storyboard.TargetProperty="(Background).(SolidColorBrush.Color)"
                                                        To="Green" />
                                    </Storyboard>
                                </BeginStoryboard>
                            </DataTrigger.EnterActions>
                            <DataTrigger.ExitActions>
                                <BeginStoryboard>
                                    <Storyboard Duration="0:0:1">
                                        <ColorAnimation Storyboard.TargetProperty="(Background).(SolidColorBrush.Color)"
                                                        To="White" />
                                    </Storyboard>
                                </BeginStoryboard>
                            </DataTrigger.ExitActions>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </ListBox.Style>
        </ListBox>
    </Grid>
</Window>

MainWindow代码隐藏：

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this;
        }
    }
}

SelectionConverter.cs

namespace WpfApplication1
{
    public class SelectionConverter : IValueConverter
    {
        #region IValueConverter Members

        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return (value == null) ? null : (value as XmlLinkedNode).SelectNodes("name")[0].InnerText;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }

        #endregion
    }
}

示例数据（以XML文件的形式添加到您的项目中）：

<?xml version="1.0" encoding="utf-8" ?>
<persons>
    <person>
        <name>a</name>
        <prop>3</prop>
    </person>
    <person>
        <name>b</name>
        <prop>3</prop>
    </person>
    <person>
        <name>c</name>
        <prop>3</prop>
    </person>
</persons>

如何基于ListBoxItem选择开始故事板？

1 个答案: