添加正确的类以水平而不是垂直显示列表项:
<ul class="@(10) @(21)">
<li class="list-group-item">First item</li>
<li class="list-group-item">Second item</li>
<li class="list-group-item">Third item</li>
</ul>
<ul class="list-group list-group-horizontal">
<li class="list-group-item">First item</li>
<li class="list-group-item">Second item</li>
<li class="list-group-item">Third item</li>
</ul>