如何有一个包含两列、三列或更多列的下拉菜单？答案

【问题标题】：How to have a dropdown menu with two, three or more columns?如何有一个包含两列、三列或更多列的下拉菜单？
【发布时间】：2019-09-27 17:23:12
【问题描述】：

默认情况下在 bootstrap 4 上注意到我只能有一个下拉菜单列，有没有办法在下拉菜单中使用网格系统，所以我可以有多个列或任何其他方法？

到目前为止，这是我的代码，但根本不起作用（请注意，sn-p 它是响应式的，因此如果分辨率太小，它将显示为移动设备而不是桌面设备）

<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
  <title></title>
</head>
<body>
<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>

  <div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Dropdown
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdown">
          <div class="container">
            <div class="row">
              <div class="col-6">
                <h6 class="dropdown-header">Header</h6>
                <a class="dropdown-item" href="#">Action</a>
                <a class="dropdown-item" href="#">Another action</a>
                <a class="dropdown-item" href="#">Something else here</a>
              </div>
              <div class="col-6">
                <h6 class="dropdown-header">Header</h6>
                <a class="dropdown-item" href="#">Action</a>
                <a class="dropdown-item" href="#">Another action</a>
                <a class="dropdown-item" href="#">Something else here</a>
              </div>
            </div>
          </div>
        </div>
      </li>
    </ul>

  </div>
</nav>

</body>
</html>

【问题讨论】：

.dropdown-menu 在这里没有得到合适的宽度，因为它是窄 LI 元素的后代，并且只设置了 min-width: 10rem;。您需要在此处增加该元素的（最小）宽度才能使其正常工作。
或从.row 元素中删除flex-wrap: wrap; - 如果您明确禁止两个弹性列分成多行，那么它们将占用所需的空间。
尝试了这两种解决方案，但列之间有很大的空间，而且它也没有响应:(不是用我放的内容自动调整宽度的方法吗？
“但是列之间有很大的空间” - .col-6 类已经带有 15px 的填充，并且您正在向左添加另外 1.5rem 的填充就在你的链接上，所以......如果你想要“更少的空间”......可能会减少后者......？

标签： html css bootstrap-4

【解决方案1】：

你也可以有两到三列，也许你没有很好地设置类

.dropdown-menu .drop {
  min-width: 400px
}

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>

<!-- 
  Bootstrap docs: https://getbootstrap.com/docs
-->

<div class="dropdown my-3">
  <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    Dropdown Menu With 2 Columns
  </button>
  <div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
    <div class="row">
      <div class="col-6">
        <a class="dropdown-item" href="#">Action</a>
        <a class="dropdown-item" href="#">Another action</a>
        <a class="dropdown-item" href="#">Something else here</a>
      </div>
      <div class="col-6">
        <a class="dropdown-item" href="#">Action</a>
        <a class="dropdown-item" href="#">Another action</a>
        <a class="dropdown-item" href="#">Something else here</a>
      </div>
    </div>
  </div>
</div>


<div class="dropdown my-3">
  <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    Dropdown Menu with 3 Columns
  </button>
  <div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
    <div class="row">
      <div class="col-4">
        <a class="dropdown-item" href="#">Action</a>
        <a class="dropdown-item" href="#">Another action</a>
        <a class="dropdown-item" href="#">Something else here</a>
      </div>
      <div class="col-4">
        <a class="dropdown-item" href="#">Action</a>
        <a class="dropdown-item" href="#">Another action</a>
        <a class="dropdown-item" href="#">Something else here</a>
      </div>
      <div class="col-4">
        <a class="dropdown-item" href="#">Action</a>
        <a class="dropdown-item" href="#">Another action</a>
        <a class="dropdown-item" href="#">Something else here</a>
      </div>
    </div>
  </div>
</div>






<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>

  <div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Dropdown
        </a>
        <div class="dropdown-menu drop" aria-labelledby="navbarDropdown">
          <div class="row">
            <div class="col-6">
              <a class="dropdown-item" href="#">Action</a>
              <a class="dropdown-item" href="#">Another action</a>
              <div class="dropdown-divider"></div>
              <a class="dropdown-item" href="#">Something else here</a>
            </div>
            <div class="col-6">
              <a class="dropdown-item" href="#">Action</a>
              <a class="dropdown-item" href="#">Another action</a>
              <div class="dropdown-divider"></div>
              <a class="dropdown-item" href="#">Something else here</a>
            </div>
          </div>
        </div>
      </li>
    </ul>
  </div>
</nav>

【讨论】：

复制并粘贴了您的代码，导航栏不起作用，但正常的下拉菜单是的
为它添加一个类“drop”以实现特异性添加 min-width prop .dropdown-menu.drop { min-width: 400px; }