Silverlight 动画：无法解析 TargetName

Question

我遇到了动画问题。首先，我尝试使用 XAML 标记中的 VisualStateManager 制作动画。这在尝试为 Opacity 属性设置动画时有效，但不适用于 Height 属性。然后我想我会通过以编程方式制作动画来尝试一下，这样我就可以更轻松地调试。因此，我不断得到以下信息：

无法解析 TargetName ExplorerBody

我不知道为什么动画不透明度有效但高度无效，我不知道为什么它无法解析 TargetName。查看我的代码，也许你能看到我看不到的东西：

    <ControlTemplate TargetType="Controls:ApplicationExplorer">                        
        <Border BorderBrush="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=BorderBrush}" 
                BorderThickness="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=BorderThickness}" 
                CornerRadius="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=CornerRadius}" 
                Width="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Width}" 
                Height="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Height}" >

            <Grid x:Name="Root" MinWidth="100">
                <Grid.RowDefinitions>
                    <RowDefinition Height="30" />
                    <RowDefinition Height="*" />
                </Grid.RowDefinitions>
                <Grid Grid.Row="0" Background="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=HeaderBackgroundBrush}">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="10" />
                        <ColumnDefinition Width="*" />
                        <ColumnDefinition Width="40" />
                    </Grid.ColumnDefinitions>
                    <TextBlock Grid.Column="1" Text="{TemplateBinding Title}" Style="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TitleStyle}" VerticalAlignment="Center" />
                    <Controls:LayoutToggleButton Grid.Column="2" x:Name="LayoutButton" Cursor="Hand" />
                </Grid>
                <Border x:Name="ExplorerBody" Background="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Background}" 
                        Grid.Row="1" HorizontalAlignment="Stretch" BorderThickness="0" >
                    <toolkit:TreeViewDragDropTarget AllowedSourceEffects="Copy" x:Name="treeViewDropTarget" 
                                            HorizontalAlignment="Left" VerticalAlignment="Top" >
                        <sdk:TreeView x:Name="treeView" ItemsSource="{TemplateBinding Nodes}" Background="Transparent" BorderThickness="0"
                            ItemTemplate="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TreeItemTemplate}" 
                            HorizontalAlignment="Left" Margin="10 0 0 0" />
                    </toolkit:TreeViewDragDropTarget>
                </Border>
            </Grid>
            <vsm:VisualStateManager.VisualStateGroups>
                <vsm:VisualStateGroup x:Name="LayoutGroup">
                    <vsm:VisualState x:Name="Minimized">
                        <Storyboard>
                            <DoubleAnimation Storyboard.TargetName="ExplorerBody" Storyboard.TargetProperty="Height" Duration="0:0:0.5" From="1"  To="0" />
                        </Storyboard>
                    </vsm:VisualState>
                    <vsm:VisualState x:Name="Maximized" />
                </vsm:VisualStateGroup>
            </vsm:VisualStateManager.VisualStateGroups>
        </Border>
    </ControlTemplate>

下面是我尝试使用 C# 代码完成它的方法：

    Storyboard storyboard = new Storyboard();
    storyboard.SetValue(Storyboard.TargetNameProperty, _explorerBody.Name);
    storyboard.SetValue(Storyboard.TargetPropertyProperty, new PropertyPath("Opacity"));
    DoubleAnimation anim = new DoubleAnimation();
    anim.Duration = new Duration(new TimeSpan(0, 0, 0, 0, 500));
    anim.To = 0;
    storyboard.Children.Add(anim);
    storyboard.Begin();

那么我的代码有什么问题？

Answer 1

您最初的尝试与 MS 文档相符 -

Storyboard storyboard = new Storyboard();

storyboard.SetValue(Storyboard.TargetNameProperty, _explorerBody.Name);

storyboard.SetValue(Storyboard.TargetPropertyProperty, new PropertyPath("Opacity"));
DoubleAnimation anim = new DoubleAnimation();

以及您的解决方案 -

    Storyboard storyboard = new Storyboard();
    storyboard.SetValue(Storyboard.TargetPropertyProperty, new PropertyPath("Opacity"));
    DoubleAnimation animation = new DoubleAnimation();
    storyboard.Children.Add(animation);
    Storyboard.SetTarget(animation, _explorerBody);

特别是替换 -

  storyboard.SetValue(Storyboard.TargetNameProperty part with -
  Storyboard.SetTarget(animation, _explorerBody);

是什么破解了它。

Answer 2

不确定 TargetName 错误，但我很确定您需要类似的东西 TargetProperty 的 (UIElement.Height)。
现在无法尝试重现您的问题，所以只是一个疯狂的猜测......

<DoubleAnimation Storyboard.TargetName="ExplorerBody" Storyboard.TargetProperty="(UIElement.Height)" Duration="0:0:0.5" From="1"  To="0" />

Answer 3

好的，我终于让它工作了......以下链接很有帮助：

http://mindfusion.eu/Forum/YaBB.pl?board=diaglite_disc;action=display;num=1278055916

这是我的代码，以防有人需要：

    private void SwitchLayoutState(object sender, RoutedEventArgs e)
    {
        if (_currentState == ControlLayout.None)
        {
            throw new ArgumentException("Control layout cannot be None.");
        }

        Duration duration = new Duration(new TimeSpan(0, 0, 0, 0, 400));
        Storyboard storyboard = new Storyboard();
        storyboard.SetValue(Storyboard.TargetPropertyProperty, new PropertyPath("Opacity"));
        DoubleAnimation animation = new DoubleAnimation();
        storyboard.Children.Add(animation);
        Storyboard.SetTarget(animation, _explorerBody);

        if (_currentState == ControlLayout.Maximized)
        {
            animation.To = 0;

            storyboard.Completed += (s, args) => { _explorerBody.Visibility = System.Windows.Visibility.Collapsed; };
            storyboard.Begin();

            _currentState = ControlLayout.Minimized;
            _layoutButton.Content = "+";
        }
        else if (_currentState == ControlLayout.Minimized)
        {
            _explorerBody.Visibility = System.Windows.Visibility.Visible;

            animation.To = 1;
            storyboard.Begin();

            _currentState = ControlLayout.Maximized;
            _layoutButton.Content = "-";
        }
    }