WPF动画依赖问题 [英] WPF Animation dependency issue

问题描述

我刚开始学习 WPF 和 XAML，并尝试在我的机器上制作动画示例.基本上，当在相应的文本框中设置特定值时，标签背景应该会发生变化.问题是我收到以下错误:Background' 属性未指向路径 '(0).(1)

I just started to learn WPF and XAML and I tried to gete an animation sample to work on my machine. Basically, a label background should change when a specific value is set in the corresponding textbox. Issue is I get the following error: Background' property does not point to a DependencyObject in path '(0).(1)

这是 XAML:

<Window x:Class="WpfDataBinding.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:loc="clr-namespace:WpfDataBinding"
    Title="MainWindow" Height="350" Width="264.828">
<Window.Resources>
    <DataTemplate DataType="{x:Type loc:Person}">
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto"/>
                <RowDefinition Height="Auto"/>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto"/>
                <ColumnDefinition Width="210"/>
            </Grid.ColumnDefinitions>
            <TextBlock Name="nameLabel" Grid.Row="0" Grid.Column="0" Text="Name:" FontSize="14" Margin="3,3,0,0"/>
            <TextBox Name="nameTextBox" Grid.Row="0" Grid.Column="1" Width="200" Text="{Binding Name}" FontSize="14" Margin="3" />
            <TextBlock Name="ageLabel" Grid.Row="1" Grid.Column="0" Text="Age:" FontSize="14" Margin="3,3,0,0"/>
            <TextBox Name="ageTextBox" Grid.Row="1" Grid.Column="1" Width="200" Text="{Binding Age}" FontSize="14" Margin="3"/>
        </Grid>
        <DataTemplate.Triggers>
            <DataTrigger Binding="{Binding Age}" Value="21">
                <DataTrigger.EnterActions>
                    <BeginStoryboard>
                        <Storyboard>
                            <ColorAnimation Storyboard.TargetName="ageLabel"
                                            Storyboard.TargetProperty="(Label.Background).(SolidColorBrush.Color)"
                                            To="Red" Duration="0:0:1"/>
                        </Storyboard>
                    </BeginStoryboard>
                </DataTrigger.EnterActions>
            </DataTrigger>
        </DataTemplate.Triggers>
    </DataTemplate>
</Window.Resources>
<Grid Margin="0,0,0,-0.2" HorizontalAlignment="Left" Width="248">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>
    <ListBox ItemsSource="{Binding}" />
    <StackPanel Grid.Row="2" Grid.ColumnSpan="2">
        <Button Content="_Show.." Click="Button_Click"/>
        <Button Content="_Age" Click="Button_Click_1"/>
    </StackPanel>
</Grid>

谢谢

推荐答案

为了在 UI 元素的 Background 属性中为 SolidColorBrush 的 Color 属性设置动画，您需要先设置背景.TextBlock 的 Background 属性的默认值为 null，因此没有任何动画.

In order to animate the Color property of a SolidColorBrush in the Background property of a UI Element, you need to first set the Background. The default value of the Background property of a TextBlock is null, so there is nothing to animate.

因此，在动画之前先设置背景:

So, first set a Background before animating it:

<TextBlock ...>
    <TextBlock.Background>
        </SolidColorBrush Color="Transparent"/>
    </TextBlock.Background>
</TextBlock>

现在您可以编写TargetProperty 路径，如

Now your could write the TargetProperty path like

Storyboard.TargetProperty="Background.Color"

或

Storyboard.TargetProperty="(TextBlock.Background).Color"

或

Storyboard.TargetProperty="(TextBlock.Background).(SolidColorBrush.Color)"

甚至

Storyboard.TargetProperty="Background.(SolidColorBrush.Color)"

所有表达式都是等价的.PropertyPath XAML 语法 MSDN 上的文章.

All expressions are equivalent. The details are explained in the PropertyPath XAML Syntax article on MSDN.

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