菜单、工具栏、StackPanel等中的垂直分隔符控件-可以吗?

也:

<Separator Style="{StaticResource {x:Static ToolBar.SeparatorStyleKey}}" />

垂直分隔符

<Style x:Key="VerticalSeparatorStyle" 
       TargetType="{x:Type Separator}"
       BasedOn="{StaticResource {x:Type Separator}}">
    <Setter Property="Margin" Value="6,0,6,0"/>
    <Setter Property="LayoutTransform">
        <Setter.Value>
            <TransformGroup>
                <TransformGroup.Children>
                    <TransformCollection>
                        <RotateTransform Angle="90"/>
                    </TransformCollection>
                </TransformGroup.Children>
            </TransformGroup>
        </Setter.Value>
    </Setter>
</Style>

可以这样用

<Separator Style="{DynamicResource VerticalSeparatorStyle}" />