绑定错误在ToolTip可见性上

Question

我试图将ToolTip的可见性属性绑定到Button的IsEnabled

 <Button Name="bbb" Content="Train" Command="{Binding TrainCmd}" ToolTipService.ShowOnDisabled="True">
      <Button.ToolTip>
          <ToolTip Content="{Binding TrainToolTip}" Visibility="{Binding IsEnabled, Converter={StaticResource InverseBooleanToVisibilityConverter}, ElementName=aaa}">
          </ToolTip>
      </Button.ToolTip>
 </Button> 

但我收到以下错误：

“ System.Windows.Data错误：4：找不到引用为'ElementName = aaa'的绑定源。BindingExpression：Path = IsEnabled; DataItem = null；目标元素为'ToolTip'（Name =''）；目标属性为'可见性”（类型为“可见性”）”

我也试过

 <Button Content="Train" Command="{Binding TrainCmd}" ToolTipService.ShowOnDisabled="True">
    <Button.ToolTip>
        <ToolTip Content="{Binding TrainToolTip}" Visibility="{Binding IsEnabled, Converter={StaticResource InverseBooleanToVisibilityConverter}, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Button}}}"/>
    </Button.ToolTip>
 </Button>

但后来我明白了

“ System.Windows.Data错误：4：找不到引用'RelativeSource FindAncestor，AncestorType ='System.Windows.Controls.Button'，AncestorLevel ='1''的绑定源。BindingExpression：Path = IsEnabled; DataItem = null;目标元素是“工具提示”（名称=“）；目标属性是“可见性”（类型“可见性”）”

Answer 1

ToolTip与它的PlacementTarget不在同一视觉树中。

 <Button Name="bbb" Content="Train" Command="{Binding TrainCmd}" ToolTipService.ShowOnDisabled="True">
      <Button.ToolTip>
           <ToolTip Content="{Binding TrainToolTip}" Visibility="{Binding PlacementTarget.IsEnabled, Converter={StaticResource InverseBooleanToVisibilityConverter}, RelativeSource={RelativeSource Self}">
            </ToolTip>
       </Button.ToolTip>
 </Button>