Question

我有以下数据触发器，但是没有触发exitactions。输入操作工作找到。我也尝试将Binding转换为布尔值以查看它是否与null有关，但这也无济于事。我有什么不对，为什么我的出境活动不在这里解雇？

<DataTrigger  Binding="{Binding }" Value="{x:Null}">
    <DataTrigger.EnterActions>
        <BeginStoryboard>
            <Storyboard>
                <DoubleAnimation Storyboard.TargetProperty="Opacity"  To=".5" From="0" Duration="0:0:1"></DoubleAnimation>
            </Storyboard>
        </BeginStoryboard>
    </DataTrigger.EnterActions>
    <DataTrigger.ExitActions>
        <BeginStoryboard>
            <Storyboard>
                <DoubleAnimation Storyboard.TargetProperty="Opacity"  To="0" From=".5" Duration="0:0:1"></DoubleAnimation>
            </Storyboard>
        </BeginStoryboard>
    </DataTrigger.ExitActions>
</DataTrigger>

编辑：必须要在这里做一些事情，因为我也尝试将故事板排除在外，只使用Setter - 现在正在发生的事情......

所以，代替这一点，我会发布整个TextBlock，也许有人可以指出我缺少的东西

<Grid DataContext="{Binding ElementName=ConfigTree, Path=SelectedItem.Details}">


                    <TextBlock HorizontalAlignment="Center" TextWrapping="Wrap" TextAlignment="Center" Padding="10" VerticalAlignment="Center" FontWeight="Bold" FontSize="14" Opacity="0">
                        Select a configuration on the right to modify its selected columns
                        <TextBlock.Style>
                            <Style TargetType="TextBlock"  BasedOn="{StaticResource {x:Type TextBlock}}">
                                <Style.Triggers>
                                    <DataTrigger  Binding="{Binding }" Value="{x:Null}">
                                        <DataTrigger.EnterActions>
                                            <BeginStoryboard>
                                                <Storyboard  Duration="0:0:1">
                                                    <DoubleAnimation Storyboard.TargetProperty="Opacity"  To=".5" From="0" Duration="0:0:1"></DoubleAnimation>
                                                </Storyboard>
                                            </BeginStoryboard>
                                        </DataTrigger.EnterActions>
                                        <DataTrigger.ExitActions>
                                            <BeginStoryboard>
                                                <Storyboard>
                                                    <DoubleAnimation Storyboard.TargetProperty="Opacity"  To="0" From=".5" Duration="0:0:1"></DoubleAnimation>
                                                </Storyboard>
                                            </BeginStoryboard>
                                        </DataTrigger.ExitActions>
                                    </DataTrigger>
                                </Style.Triggers>
                            </Style>
                        </TextBlock.Style>
                    </TextBlock>

ConfigTree是一个树视图，SelectedItem.Details是一个实现observablecollection和INotifyPropertyChanged的类。我已经检查过调试器，这个绑定正在正确更新，并且来回切换到我的实例值和空值。

Answer 1

我工作得很好！

         <CheckBox x:Name="MyCheckBox"
                   IsThreeState="True"
                   Content="I am Tristate! Check Me"/>

         <TextBox x:Name="MyTextBlock"
                  Background="Cyan"
                  Text="1234567890">
            <TextBox.Style>
                <Style TargetType="{x:Type TextBox}">
                    <Style.Triggers>
                        <DataTrigger 
                            Binding="{Binding ElementName=MyCheckBox,
                                              Path=IsChecked}"
                            Value="{x:Null}">
                            <DataTrigger.EnterActions>
                                <BeginStoryboard>
                                    <Storyboard>
                                        <DoubleAnimation
                                          Storyboard.TargetProperty="Opacity"
                                          To=".5" From="0"
                                          Duration="0:0:1">
                                        </DoubleAnimation>
                                    </Storyboard>
                                </BeginStoryboard>
                            </DataTrigger.EnterActions>
                            <DataTrigger.ExitActions>
                                <BeginStoryboard>
                                    <Storyboard>
                                        <DoubleAnimation
                                          Storyboard.TargetProperty="Opacity"
                                          To="0" From="0.5"
                                          Duration="0:0:1">
                                        </DoubleAnimation>
                                    </Storyboard>
                                </BeginStoryboard>
                            </DataTrigger.ExitActions>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </TextBox.Style>
        </TextBox>

DataTrigger.ExistActions未触发绑定值“null”

1 个答案: