>>553
これじゃダメなん？

<ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Disabled">
<WrapPanel Orientation="Vertical">
<TextBlock Text="1" />
<TextBlock Text="2" />
<TextBlock Text="3" />
<TextBlock Text="4" />
<TextBlock Text="5" />
<TextBlock Text="6" />
<TextBlock Text="7" />
<TextBlock Text="8" />
</WrapPanel>
</ScrollViewer>