试图以动画的高度，但得到错误的高度为NaN [英] Trying to animate height but getting error that height is NaN

问题描述

在试图创建一个动画，动态地调整高度。我发现此信息，帮助，但是当我尝试使用它，我得到一个错误：System.Windows.Media.Animation.DoubleAnimation'不能使用的'南的默认目标值

如果我指定的高度，我得到这个错误。

风格：

 ＆LT;风格X：键=bdrSlideIn
   的TargetType ={X：边框类型}＆GT;
        ＆LT; Style.Resources＆GT;
            ＆LT;情节提要X：键=storyBoardIn＆GT;
                ＆LT; D​​oubleAnimation是的BeginTime =00:00:00
                                 从=0
                                 持续时间=00：00：00.65
                                 Storyboard.TargetName ={X：空}
                                 Storyboard.TargetProperty =（FrameworkElement.Height）
                                 DecelerationRatio =1/＆GT;
            ＆LT; /故事板＆GT;            ＆LT;情节提要X：键=storyBoardOut＆GT;
                ＆LT; D​​oubleAnimation是的BeginTime =00:00:00
                                 为=0
                                 持续时间=00：00：00.65
                                 Storyboard.TargetName ={X：空}
                                 Storyboard.TargetProperty =（FrameworkElement.Height）
                                 AccelerationRatio =1/＆GT;
            ＆LT; /故事板＆GT;
        ＆LT; /Style.Resources>        ＆LT; Style.Triggers＆GT;
            ＆LT; D​​ataTrigger绑定={结合SearchExecuted}
                         值=真＆GT;
                ＆LT; D​​ataTrigger.EnterActions＆GT;
                    ＆LT; BeginStoryboard故事板={StaticResource的storyBoardIn}
                                     NAME =SlideStoryboard/＆GT;
                ＆LT; /DataTrigger.EnterActions>
                ＆LT; D​​ataTrigger.ExitActions＆GT;
                    ＆LT; BeginStoryboard故事板={StaticResource的storyBoardOut}/＆GT;
                ＆LT; /DataTrigger.ExitActions>
            ＆LT; / DataTrigger＆GT;
        ＆LT; /Style.Triggers>
    ＆LT; /样式和GT;
 

边框：

 ＆LT; BORDER = VerticalAlignment顶部
    风格={StaticResource的bdrSlideIn}＆GT;
        ＆LT; WPFToolKit：DataGrid的名称=dgSearchResults
                             的ItemsSource ={结合的SearchResult}
                             了maxHeight =280
                             VerticalAlignment =评出的＆GT; ...
 

解决方案

如果你想保持高度动态的，那么你不能直接动画身高：正如你所看到的，除非你明确地赋值WPF会尝试向插值。NaN的结果相反，给你的元素LayoutTransform＆LT; ScaleTransform /＆gt;和动画这种转变的scaleX和scaleY参数

Been trying to create an animation to dynamically adjust height. I found this info that helped but when I try to use it I get an error: 'System.Windows.Media.Animation.DoubleAnimation' cannot use default destination value of 'NaN'.

If I specify the height I get that error.

Style:

<Style x:Key="bdrSlideIn"
   TargetType="{x:Type Border}">
        <Style.Resources>
            <Storyboard x:Key="storyBoardIn">
                <DoubleAnimation BeginTime="00:00:00"
                                 From="0"
                                 Duration="00:00:00.65"
                                 Storyboard.TargetName="{x:Null}"
                                 Storyboard.TargetProperty="(FrameworkElement.Height)"
                                 DecelerationRatio="1" />
            </Storyboard>

            <Storyboard x:Key="storyBoardOut">
                <DoubleAnimation BeginTime="00:00:00"
                                 To="0"
                                 Duration="00:00:00.65"
                                 Storyboard.TargetName="{x:Null}"
                                 Storyboard.TargetProperty="(FrameworkElement.Height)"
                                 AccelerationRatio="1" />
            </Storyboard>
        </Style.Resources>

        <Style.Triggers>
            <DataTrigger Binding="{Binding SearchExecuted}"
                         Value="True">
                <DataTrigger.EnterActions>
                    <BeginStoryboard Storyboard="{StaticResource storyBoardIn}"
                                     Name="SlideStoryboard" />
                </DataTrigger.EnterActions>
                <DataTrigger.ExitActions>
                    <BeginStoryboard Storyboard="{StaticResource storyBoardOut}" />
                </DataTrigger.ExitActions>
            </DataTrigger>
        </Style.Triggers>
    </Style>

Border:

<Border VerticalAlignment="Top"
    Style="{StaticResource bdrSlideIn}">
        <WPFToolKit:DataGrid Name="dgSearchResults"
                             ItemsSource="{Binding SearchResults}"
                             MaxHeight="280"
                             VerticalAlignment="Top">...

解决方案

If you want to keep Height dynamic then you can't animate Height directly: As you've seen, unless you explicitly assign it WPF will try to interpolate to NaN.
Instead, give your element a LayoutTransform <ScaleTransform/>, and animate the ScaleX and ScaleY parameters of that transformation.

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