TemplateBinding没有传递给ControlTemplate.Resources中创建的VisualBrush

我提前道歉，因为我确定这篇文章之前已经发布过了，我只是似乎不知道如何正确地表达它来找到答案。

我试图创建一个CueTextBox样式模板(所以当它是空的，它显示的工具提示在一个变亮的颜色)，但它似乎不会传递{TemplateBinding属性=工具提示}到标签的内容…如果我只是用文本替换它，它工作得很好，但我不能让它绑定到文本框的工具提示。

下面是代码

<Style x:Key="CueTextBox" TargetType="TextBox" xmlns:sys="clr-namespace:System;assembly=mscorlib">
    <Setter Property="Background" Value="#1e1e1e" />
    <Setter Property="Foreground" Value="White" />
    <Setter Property="BorderBrush" Value="#434346" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type TextBox}">
                <Border x:Name="Bd" 
                    Background="{TemplateBinding Background}" 
                    BorderBrush="{TemplateBinding BorderBrush}"
                    BorderThickness="{TemplateBinding BorderThickness}" 
                    CornerRadius="0">
                    <ScrollViewer VerticalAlignment="Center" Background="{TemplateBinding Background}" Foreground="{TemplateBinding Foreground}"  x:Name="PART_ContentHost"/>
                </Border>
                <ControlTemplate.Resources>
                    <VisualBrush x:Key="CueBannerBrush" AlignmentX="Left" AlignmentY="Center" Stretch="None">
                        <VisualBrush.Visual>
                            <Label Padding="5,0" Content="{TemplateBinding Property=ToolTip}" Foreground="#888888" />
                        </VisualBrush.Visual>
                    </VisualBrush>
                </ControlTemplate.Resources>
                <ControlTemplate.Triggers>
                    <MultiTrigger>
                        <MultiTrigger.Conditions>
                            <Condition Property="IsMouseOver" Value="true" />
                            <Condition Property="Text" Value="{x:Null}" />
                        </MultiTrigger.Conditions>
                        <Setter Property="Background" Value="{StaticResource CueBannerBrush}"/>
                    </MultiTrigger>
                    <MultiTrigger>
                        <MultiTrigger.Conditions>
                            <Condition Property="IsMouseOver" Value="true" />
                            <Condition Property="Text" Value="{x:Static sys:String.Empty}" />
                        </MultiTrigger.Conditions>
                        <Setter Property="Background" Value="{StaticResource CueBannerBrush}"/>
                    </MultiTrigger>
                    <Trigger Property="Text" Value="{x:Static sys:String.Empty}">
                        <Setter Property="Background" Value="{StaticResource CueBannerBrush}" />
                    </Trigger>
                    <Trigger Property="Text" Value="{x:Null}">
                        <Setter Property="Background" Value="{StaticResource CueBannerBrush}" />
                    </Trigger>
                    <Trigger Property="IsKeyboardFocused" Value="True">
                        <Setter Property="Background" Value="#1e1e1e" />
                        <Setter Property="BorderBrush" Value="#007acc" />
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

用法:

<TextBox ToolTip="First Name" Style="{StaticResource CueTextBox}" />