WPF可见性绑定与绑定到可见性的数据触发器配合不好

Question

我不知道这段代码有什么问题。也许你能发现我看不到的东西。我的项目建设得很好，设计师没有抱怨任何事情。但是，当我尝试运行它时，它说它不能创建该代码所在窗口的实例。

我认为我已经将问题缩小到与数据触发器协调的可见性绑定。如果我删除该属性的可见性绑定，并将其任意设置为true或false，它运行得很好。但我需要这个属性是动态的。

<Image Visibility="{Binding ShowStatusMessageTabIcon, Converter={StaticResource BoolToVisibility}}"
   Source="{Binding Source={x:Static bo:UserSession.Instance}, Path=HighestStatusMessageSeverity, Converter={StaticResource SeverityToImageConverter}}">
<Image.Style>
    <Style>
        <Style.Triggers>
            <DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=Visibility}"
                         Value="Visible">
                <DataTrigger.EnterActions>
                    <BeginStoryboard Storyboard="{StaticResource FlashErrorImage}" />
                </DataTrigger.EnterActions>
                <DataTrigger.ExitActions>
                    <RemoveStoryboard BeginStoryboardName="FlashErrorImage" />
                </DataTrigger.ExitActions>
            </DataTrigger>
        </Style.Triggers>
    </Style>
</Image.Style>

Answer 1

如果您在UIElement本身的属性上使用Trigger，您将希望使用Trigger而不是DataTrigger，DataTriggers更多用于模型中DataObjects的更改等，普通Triggers用于UIElements等。

   <Image.Style>
        <Style TargetType="{x:Type Image}">
            <Style.Triggers>
                <Trigger Property="Visibility" Value="Visible">
                    <Trigger.EnterActions>
                        <BeginStoryboard Storyboard="{StaticResource FlashErrorImage}" />
                    </Trigger.EnterActions>
                    <Trigger.ExitActions>
                        <RemoveStoryboard BeginStoryboardName="FlashErrorImage" />
                    </Trigger.ExitActions>
                </Trigger>
            </Style.Triggers>
        </Style>
    </Image.Style>

这是一个完整的工作模型，如果它有助于缩小问题

Xaml:

<Window x:Class="WpfApplication7.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" Name="UI">
    <Window.Resources>
        <BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" />
        <Storyboard x:Key="FadeAnimation" Storyboard.TargetProperty="Opacity" >
            <DoubleAnimation From="0" To="1" Duration="0:0:5" />
        </Storyboard>
    </Window.Resources>
    <StackPanel>
        <Image Source="http://icons.iconarchive.com/icons/iconcreme/halloween/128/Skeleton-icon.png" 
               Visibility="{Binding ElementName=UI, Path=ImageVisible, Converter={StaticResource BooleanToVisibilityConverter}}" Height="247">
        <Image.Style>
            <Style TargetType="{x:Type Image}">
                <Style.Triggers>
                    <Trigger Property="Visibility" Value="Visible">
                        <Trigger.EnterActions>
                                <BeginStoryboard Name="Fade" Storyboard="{StaticResource FadeAnimation}" />
                        </Trigger.EnterActions>
                        <Trigger.ExitActions>
                             <RemoveStoryboard BeginStoryboardName="Fade"  />
                        </Trigger.ExitActions>
                    </Trigger>
                </Style.Triggers>
            </Style>
        </Image.Style>
    </Image>
        <Button Click="Button_Click" Content="Visible"/>
    </StackPanel>
</Window>

代码：

public partial class MainWindow : Window, INotifyPropertyChanged
{
    private bool _imageVisible;
    public MainWindow()
    {
        InitializeComponent();
    }
    public bool ImageVisible
    {
        get { return _imageVisible; }
        set { _imageVisible = value; NotifyPropertyChanged("ImageVisible"); }
    }
    private void Button_Click(object sender, RoutedEventArgs e)
    {
        ImageVisible = !ImageVisible;
    }
    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged(string p)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(p));
        }
    }
}