IsPressed触发器（按钮）导致异常

我试图重写按钮样式。其实我已经做了几十次，但现在我碰到这个传来：IsPressed触发器（按钮）导致异常

异常和的InnerException： {“属性不能在触发空”}

我的代码：

<Style x:Key="ArrowRightStyle" TargetType="{x:Type Button}"> 
    <Setter Property="FocusVisualStyle" Value="{StaticResource ButtonFocusVisual}"/> 
    <Setter Property="Background" Value="{StaticResource ButtonNormalBackground}"/> 
    <Setter Property="BorderBrush" Value="{StaticResource ButtonNormalBorder}"/> 
    <Setter Property="BorderThickness" Value="0"/> 
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/> 
    <Setter Property="HorizontalContentAlignment" Value="Center"/> 
    <Setter Property="VerticalContentAlignment" Value="Center"/> 
    <Setter Property="Padding" Value="1"/> 
    <Setter Property="Template"> 
     <Setter.Value> 
      <ControlTemplate> 
       <Grid Height="{Binding ElementName=imgBackground, Path=ActualHeight, Mode=OneWay}" 
         Width="{Binding ElementName=imgBackground, Path=ActualWidth, Mode=OneWay}"> 
        <Image x:Name="imgBackground" Source="{StaticResource RightArrowImageNormal}" Stretch="None"/> 
       </Grid> 
       <ControlTemplate.Triggers> 
        <Trigger Property="IsEnabled" Value="False"> 
         <Setter TargetName="imgBackground" Property="Source" Value="{StaticResource RightArrowImageDisabled}"/> 
        </Trigger> 
        <Trigger Property="IsPressed" Value="True"> 
         <Setter TargetName="imgBackground" Property="Source" Value="{StaticResource RightArrowImageIsPressed}"/> 
        </Trigger> 
       </ControlTemplate.Triggers> 
      </ControlTemplate> 
     </Setter.Value> 
    </Setter> 

</Style>

，所以它的工作原理：

<Style x:Key="ArrowRightStyle" TargetType="{x:Type Button}"> 
    <Setter Property="FocusVisualStyle" Value="{StaticResource ButtonFocusVisual}"/> 
    <Setter Property="Background" Value="{StaticResource ButtonNormalBackground}"/> 
    <Setter Property="BorderBrush" Value="{StaticResource ButtonNormalBorder}"/> 
    <Setter Property="BorderThickness" Value="0"/> 
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/> 
    <Setter Property="HorizontalContentAlignment" Value="Center"/> 
    <Setter Property="VerticalContentAlignment" Value="Center"/> 
    <Setter Property="Padding" Value="1"/> 
    <Setter Property="Template"> 
     <Setter.Value> 
      <ControlTemplate> 
       <Grid Height="{Binding ElementName=imgBackground, Path=ActualHeight, Mode=OneWay}" 
         Width="{Binding ElementName=imgBackground, Path=ActualWidth, Mode=OneWay}"> 
        <Image x:Name="imgBackground" Source="{StaticResource RightArrowImageNormal}" Stretch="None"/> 
       </Grid> 
       <ControlTemplate.Triggers> 
        <Trigger Property="IsEnabled" Value="False"> 
         <Setter TargetName="imgBackground" Property="Source" Value="{StaticResource RightArrowImageDisabled}"/> 
        </Trigger> 
        <DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=Self}, Path=IsPressed}" Value="True"> 
         <Setter TargetName="imgBackground" 
           Property="Source" Value="{StaticResource RightArrowImageIsPressed}"/> 
        </DataTrigger> 
       </ControlTemplate.Triggers> 
      </ControlTemplate> 
     </Setter.Value> 
    </Setter> 
</Style>

为什么????

来源

2012-05-03 J. Lennon

刚刚从快看，我认为它无法找到物业IsPressed

添加“按钮。”应该这样做。

.... 
    <Trigger Property="Button.IsPressed" Value="True"> 
    <Setter TargetName="imgBackground" Property="Source" Value="{StaticResource....

，或者确保您的模板针对一个按钮（我知道你指定的样式，但这是不够的 - 模板将承担typeof运算（控制）和控制上没有它IsPressed 。

... 
<Setter Property="Template"> 
      <Setter.Value> 
       <ControlTemplate TargetType="{x:Type Button}"> 
      ....the rest of your code

我认为

{Binding RelativeSource={RelativeSource Mode=Self}, Path=IsPressed}"

在运行时解析相对源的类型为 “按钮”，因此能够找到IsPressed ...

来源

2012-05-03 21:34:26

IsPressed触发器（按钮）导致异常

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