如何在WPF中设置右边框MenuItem

Question

我有3列菜单项，但第1列具有右边框，第2,3列没有。 为第2、3列设置右边界。请告诉我。 Image Herer https://i.stack.imgur.com/oRpug.png ................................................... ........................

MainWindow.xaml

<Window x:Class="TestMutilColumnMenu.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:TestMutilColumnMenu"
    mc:Ignorable="d"
    Title="MainWindow" Height="350" Width="525">
<Menu>
    <MenuItem x:Name="tesst" Header="nane" >
        <MenuItem.ItemsPanel>
            <ItemsPanelTemplate>
                <Grid VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition/>
                        <ColumnDefinition/>
                        <ColumnDefinition/>
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition/>
                        <RowDefinition/>
                        <RowDefinition/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                </Grid>
            </ItemsPanelTemplate>
        </MenuItem.ItemsPanel>
        <MenuItem Grid.Row="0" Grid.Column="0"  Header="Item 1" >
            <MenuItem.Icon>
                <Image Source="/res/Image.png"/>
            </MenuItem.Icon>
        </MenuItem>
    <MenuItem  Grid.Row="1" Grid.Column="0" Header="Item 2">
            <MenuItem.Icon>
                <Image Source="/res/Image.png"/>
            </MenuItem.Icon>
        </MenuItem>
        <MenuItem Grid.Row="2" Grid.Column="0" Header="Item 3" ></MenuItem>
        <MenuItem Grid.Row="3" Grid.Column="0" Header="Item 4" ></MenuItem>
        <MenuItem Grid.Row="0" Grid.Column="1" Header="Item 5" >
            <MenuItem.Icon>
                <Image Source="/res/Image.png"/>
            </MenuItem.Icon>
        </MenuItem>
        <MenuItem Grid.Row="1" Grid.Column="1" Header="Item 6">
            <MenuItem.Icon>
                <Image Source="/res/Image.png"/>
            </MenuItem.Icon>
        </MenuItem>
        <MenuItem Grid.Row="2" Grid.Column="1" Header="Item 7">
            <MenuItem.Icon>
                <Image Source="/res/Image.png"/>
            </MenuItem.Icon>
        </MenuItem>
        <MenuItem Grid.Row="3" Grid.Column="1" Header="Item 8"></MenuItem>
        <MenuItem Grid.Row="0" Grid.Column="2" Header="Item 9"></MenuItem>
        <MenuItem Grid.Row="1" Grid.Column="2" Header="Item 10"></MenuItem>
    </MenuItem>
</Menu>

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