Grid in ScrollViewer doesn't scroll horizontally

Question

I think I'm missing something simple here... how do I get a Grid inside a ScrollViewer to scroll horizontally? I've enabled HorizontalScrollMode , and the content is definitely long enough that it runs off the screen, but it doesn't scroll. Here's the offending code (this ScrollViewer is the lone content of a row of the LayoutRoot Grid ):

<ScrollViewer Grid.Row="1" VerticalScrollMode="Disabled"
              VerticalScrollBarVisibility="Hidden"
              HorizontalScrollMode="Enabled">
    <Grid Margin="120,0,0,100">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="240"/>
            <ColumnDefinition Width="20"/>
            <ColumnDefinition Width="240"/>
            <ColumnDefinition Width="20"/>
            <ColumnDefinition Width="240"/>
            <ColumnDefinition Width="20"/>
            <ColumnDefinition Width="240"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <TextBlock Text="Download" HorizontalAlignment="Center" Margin="0,0,0,10"/>
        <local:BandwidthMeter Grid.Row="1" x:Name="PolicyDown" Grid.Column="0"/>
        <TextBlock Grid.Column="2" Text="Upload" HorizontalAlignment="Center"/>
        <local:BandwidthMeter Grid.Row="1" x:Name="PolicyUp" Grid.Column="2"/>
        <TextBlock Grid.Column="4" Text="Download" HorizontalAlignment="Center"/>
        <local:BandwidthMeter x:Name="ActualDown" Grid.Row="1" Grid.Column="4"/>
        <TextBlock Grid.Column="6" Text="Upload" HorizontalAlignment="Center"/>
        <local:BandwidthMeter x:Name="ActualUp" Grid.Row="1" Grid.Column="6" />
        <TextBlock Grid.Column="7" Text="Campus-wide bandwidth usage" HorizontalAlignment="Center"/>
        <Image Grid.Column="7" Grid.Row="1" Margin="80,0,0,0" Source="[image URL]" Stretch="UniformToFill"/>
    </Grid>
</ScrollViewer>

Answer 1

将属性HorizontalScrollBarVisibility="Auto"到ScrollViewer 。