EventTrigger 和 DataTrigger 不能一起工作

如何解决EventTrigger 和 DataTrigger 不能一起工作

我有一组要显示在 ItemsControl 中的项目。 当一个项目是新的时，它应该淡入，当它的 StateType 属性更改为“完成”时，它应该淡出。

我的ItemTemplate的{​​{1}}是ItemsControl

DockPanel

问题是：它淡入但永不淡出。如果我将 <DockPanel.Style> <Style TargetType="{x:Type DockPanel}"> <Style.Triggers> <!-- Fades in as expected but DataTrigger below never fades out --> <EventTrigger RoutedEvent="Loaded"> <BeginStoryboard> <Storyboard> <DoubleAnimation Storyboard.TargetProperty="Opacity" Duration="0:0:1" From="0" To="1"/> </Storyboard> </BeginStoryboard> </EventTrigger> <!-- Using this for fading in everything works fine (first StateType of a new item is Running) --> <!-- <DataTrigger Binding="{Binding StateType}" Value="{x:Static local:AppStateItem+Type.Running}"> <DataTrigger.EnterActions> <BeginStoryboard> <Storyboard> <DoubleAnimation Storyboard.TargetProperty="Opacity" Duration="0:0:1" From="0" To="1"/> </Storyboard> </BeginStoryboard> </DataTrigger.EnterActions> </DataTrigger> --> <!-- fade out trigger --> <DataTrigger Binding="{Binding StateType}" Value="{x:Static local:AppStateItem+Type.Finished}"> <DataTrigger.EnterActions> <BeginStoryboard> <Storyboard> <DoubleAnimation Storyboard.TargetProperty="Opacity" Duration="0:0:1" From="1" To="0" BeginTime="0:0:4"/> </Storyboard> </BeginStoryboard> </DataTrigger.EnterActions> </DataTrigger> </Style.Triggers> </Style> </DockPanel.Style> 替换为带注释的 EventTrigger 以使其淡入淡出，它会按预期工作。 DataTrigger 是否覆盖了某些东西，即使它应该只触发一次？

解决方法

您的示例在使用两个 #include<bits/stdc++.h> using namespace std; int main() { unordered_map<int,string>mp; mp[1]="Sunday"; mp[2]="Mon"; mp[3]="Tue"; mp[4]="Wed"; mp[5]="Thu"; mp[6]="Fri"; mp[7]="Sat"; int n; cin>>n; cout<<mp[n%7]<<endl; } 时效果很好。

确保实现 DataTriggers 并引发 INotifyPropertyChanged 属性的 PropertyChanged 事件。

您可能还想从第二个 StateType 中删除 BeginTime 设置。

试试这个最小的可重复样本：

MainWindow.xaml：

Storyboard

MainWindow.xaml.cs：

<Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp1"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <DockPanel>
        <DockPanel.Style>
            <Style TargetType="{x:Type DockPanel}">
                <Style.Triggers>
                    <DataTrigger Binding="{Binding StateType}" Value="{x:Static local:AppStateItem.Running}">
                        <DataTrigger.EnterActions>
                            <BeginStoryboard>
                                <Storyboard >
                                    <DoubleAnimation Storyboard.TargetProperty="Opacity" Duration="0:0:1" From="0" To="1"/>
                                </Storyboard>
                            </BeginStoryboard>
                        </DataTrigger.EnterActions>
                    </DataTrigger>
                    <!-- fade out trigger -->
                    <DataTrigger Binding="{Binding StateType}" Value="{x:Static local:AppStateItem.Finished}">
                        <DataTrigger.EnterActions>
                            <BeginStoryboard>
                                <Storyboard>
                                    <DoubleAnimation Storyboard.TargetProperty="Opacity" Duration="0:0:1" From="1" To="0" />
                                </Storyboard>
                            </BeginStoryboard>
                        </DataTrigger.EnterActions>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </DockPanel.Style>
        <Button Content="Fade out" Click="Button_Click" DockPanel.Dock="Bottom" />
        <TextBlock FontSize="14" FontWeight="Bold" Text="test" />
    </DockPanel>
</Window>