WPF Trigger的问题

Question

我有两个指向同一TargetType的Style，x:Key分别是A和B。现在有一个TargetType的控件，我想让它在平常态时Style为A，满足某个DataTrigger的条件时Style为B，该如何实现？

Answer 1

一种是后台写代码来实现，另一种是2个重叠的分别应用2种Style的控件，然后根据DataTrigger设置他们的Visibility。

Answer 2

刚试了下。也可以这样写，在外面套层ContentControl然后把你的控件写在Template里面在设置就行。
如下：<Label >
            <Label.Template>
                <ControlTemplate>
                    <Label Name="TestLB"/>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter TargetName="TestLB" Property="Style" Value="{StaticResource NumLabel}"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
                
            </Label.Template>
        </Label>

Answer 3

谢谢。有一个问题，我用的是DataTrigger，在Template用ElementName获取不到模板外部的控件。请问如何解决？

Answer 4

把你的代码贴出这部分来看下。不能把整个都套在这一层ContentControl里么？

Answer 5

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition />
        </Grid.RowDefinitions>
        <StackPanel Grid.Row="0" Orientation="Horizontal">
            <Rectangle Width="50" Height="50" Fill="Red" x:Name="rectRed" Visibility="Visible" />
            <Rectangle Width="50" Height="50" Fill="Blue" x:Name="rectBlue" Visibility="Collapsed" />
        </StackPanel>
        <StackPanel Grid.Row="1" Orientation="Horizontal">
            <Button Width="50" Height="50" Content="Red" x:Name="btnRed" />
            <!-- 我想让这个按钮在rectRed的Visibility为Visible时用ActiveStyle，否则用NormanStyle -->
            <Button Width="50" Height="50" Content="Red" x:Name="btnBlue" />
            <!-- 我想让这个按钮在rectBlue的Visibility为Visible时用ActiveStyle，否则用NormanStyle -->
        </StackPanel>
    </Grid>
    <Window.Resources>
        <Style TargetType="Button" x:Key="NormanStyle">
            <Setter Property="Background" Value="Gray" />
        </Style>
        <Style TargetType="Button" x:Key="ActiveStyle">
            <Setter Property="Background" Value="Yellow" />
        </Style>
    </Window.Resources>
]

Answer 6

<Window.Resources>
        <Style TargetType="Button" x:Key="NormanStyle">
            <Setter Property="Background" Value="Gray" />
        </Style>
        <Style TargetType="Button" x:Key="ActiveStyle">
            <Setter Property="Background" Value="Yellow" />
        </Style>
    </Window.Resources>
    <Grid>
        <Label>
            <Label.Template>
                <ControlTemplate>
                    <Grid>
                    <Grid.RowDefinitions>
                        <RowDefinition />
                        <RowDefinition />
                    </Grid.RowDefinitions>
                    <StackPanel Grid.Row="0" Orientation="Horizontal">
                        <Rectangle Width="50" Height="50" Fill="Red" x:Name="rectRed" Visibility="Visible" />
                        <Rectangle Width="50" Height="50" Fill="Blue" x:Name="rectBlue" Visibility="Collapsed" />
                    </StackPanel>
                    <StackPanel Grid.Row="1" Orientation="Horizontal">
                            <Button Width="50" Height="50" Content="Red" x:Name="btnRed" Style="{StaticResource NormanStyle}"/>
                        <!-- 我想让这个按钮在rectRed的Visibility为Visible时用ActiveStyle，否则用NormanStyle -->
                            <Button Width="50" Height="50" Content="Red" x:Name="btnBlue" Style="{StaticResource NormanStyle}"/>
                        <!-- 我想让这个按钮在rectBlue的Visibility为Visible时用ActiveStyle，否则用NormanStyle -->
                    </StackPanel>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <DataTrigger Binding="{Binding ElementName=rectRed,Path=Visibility}" Value="Visible">
                            <Setter Property="Style" TargetName="btnRed" Value="{StaticResource ActiveStyle}"/>
                        </DataTrigger>
                        <DataTrigger Binding="{Binding ElementName=rectBlue,Path=Visibility}" Value="Visible">
                            <Setter Property="Style" TargetName="btnBlue" Value="{StaticResource ActiveStyle}"/>
                        </DataTrigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Label.Template>
        </Label>
    </Grid>

Answer 7

就是在最外层套一个Label之类的ContentControl，然后你的东西全写在里面的Template中，这样触发器就好控制了。

Answer 8

数据绑定你想要操作的属性之类的，后台直接操作这些数据一样吧。类似MVVM的开发模式，控件的操作，内容呈现都在后台以修改绑定数据来执行。
后台想得到控件也是可以的，用GetTemplateChild()方法就是。

Answer 9

用FindName()吧，GetTemplateChild()不是public的。

Answer 10

把按钮的Visibility和你关心的长方形的Visibility都绑定到同一个属性，直接控制那个属性，当然dataTrigger也可以根据这个属性的Value进行绑定了

Answer 11

或者 试试这样   <DataTrigger Binding="{Binding ElementName=rectRed,Path=Visibility}"  Value="Visible">
       .........
   </DataTrigger>

Answer 12

我以前遇到过类似问题，我是这样解决的，只写一个style，在datatrigger里重写controltemplate，两种datatrigger，重写两次就行。
大概是这个意思：                        <Style >
                            <Style.Triggers>
                                <DataTrigger A>
                                    <Setter Property ="Template">
                                        <Setter.Value>
                                            <ControlTemplate />
                                        </Setter.Value>
                                    </Setter>
                                </DataTrigger>
                                <DataTrigger B>
                                    <Setter Property ="Template">
                                        <Setter.Value>
                                            <ControlTemplate />
                                        </Setter.Value>
                                    </Setter>
                                </DataTrigger>
                            </Style.Triggers>
                        </Style >