如何在XAML中将CueBanner应用于文本框

我想要一个带有CueBanner的TextBox，但是它仍然无法正常工作。我做错了什么？我认为问题在于我正在{RelativeSource TemplatedParent}参考资料中使用。在不投入资源的情况下如何做到这一点？

我的XAML程式码：

<Style TargetType="{x:Type TextBox}">
    <Setter Property="SnapsToDevicePixels" Value="True" />
    <Setter Property="OverridesDefaultStyle" Value="True" />
    <Setter Property="KeyboardNavigation.TabNavigation" Value="None" />
    <Setter Property="FocusVisualStyle" Value="{x:Null}" />
    <Setter Property="MinWidth" Value="120" />
    <Setter Property="MinHeight" Value="20" />
    <Setter Property="AllowDrop" Value="true" />

    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type TextBox}">
                <ControlTemplate.Resources>
                    <VisualBrush x:Key="CueBannerBrush" AlignmentX="Left" AlignmentY="Center" Stretch="None">
                        <VisualBrush.Visual>
                            <Label Content="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Tag}"
                                       Foreground="LightGray" />
                        </VisualBrush.Visual>
                    </VisualBrush>
                </ControlTemplate.Resources>

                <Border x:Name="Border" CornerRadius="0" Padding="2" BorderThickness="1" BorderBrush="Black">
                    <ScrollViewer Margin="0" x:Name="PART_ContentHost" />
                </Border>

                <ControlTemplate.Triggers>
                    <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="LightGreen"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

感谢您的任何建议。

编辑

我的问题已解决，这是我的最终解决方案：

<Style TargetType="{x:Type TextBox}">
    <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"/>
    <Setter Property="BorderBrush" Value="Gray"/>
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
    <Setter Property="BorderThickness" Value="1"/>
    <Setter Property="KeyboardNavigation.TabNavigation" Value="None"/>
    <Setter Property="HorizontalContentAlignment" Value="Left"/>
    <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
    <Setter Property="AllowDrop" Value="true"/>
    <Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst"/>
    <Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
    <Setter Property="SnapsToDevicePixels" Value="True" />
    <Setter Property="OverridesDefaultStyle" Value="True" />

    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type TextBox}">
                <Border x:Name="Border" CornerRadius="0" Padding="2" 
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="1"
                        Background="{TemplateBinding Background}">
                    <Grid>
                        <ScrollViewer Margin="0" x:Name="PART_ContentHost" />
                        <TextBlock x:Name="Watermark"
                               Text="{Binding Tag, RelativeSource={RelativeSource TemplatedParent}}"
                               Foreground="LightGray" Margin="5,0" Visibility="Collapsed"/>
                    </Grid>
                </Border>

                <ControlTemplate.Triggers>
                    <Trigger Property="Text" Value="{x:Static sys:String.Empty}">
                        <Setter Property="Visibility" TargetName="Watermark" Value="Visible" />
                    </Trigger>
                    <Trigger Property="Text" Value="{x:Null}">
                        <Setter Property="Visibility" TargetName="Watermark" Value="Visible" />
                    </Trigger>
                    <Trigger Property="IsMouseCaptured" Value="True">
                        <Setter Property="Visibility" TargetName="Watermark" Value="Collapsed"/>
                    </Trigger>
                    <Trigger Property="IsEnabled" Value="false">
                        <Setter Property="Opacity" TargetName="Border" Value="0.56"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>

    <Style.Triggers>
        <Trigger Property="IsMouseOver" Value="True">
            <Setter Property="Cursor" Value="IBeam" />
        </Trigger>
    </Style.Triggers>
</Style>