列

借助我们的 flexbox 网格系统，了解如何使用对齐、排序和偏移选项来修改列。另外，了解如何使用列类来管理非网格元素的宽度。

内容提要

请注意！在深入了解如何修改和自定义网格列之前，请务必先阅读网格介绍页面。

工作原理

列是基于网格的 flexbox 架构。 Flexbox 意味着我们可以选择更改单个列或在以下行级别修改列组。您可以选择列如何增长、缩小或以其他方式更改。
在使用网格布局时，所有内容都放在列中。 Bootstrap 网格的层次结构从容器到行到列再到你的内容。只有极少数情况下，您可以将列和其它内容结合使用，请注意可能会产生意想不到的后果。
Bootstrap 包含了用于快速创建响应式布局的预定义类。在每个网格层具有六个断点，我们已经为您构建了几十个类来创建您想要的布局。如果您愿意，可以通过 Sass 禁用此功能。

对齐

使用 flexbox 对齐实用程序来垂直和水平对齐列。

垂直对齐

One of three columns

<div class="container">
  <div class="row align-items-start">
    <div class="col">
      One of three columns
    </div>
    <div class="col">
      One of three columns
    </div>
    <div class="col">
      One of three columns
    </div>
  </div>
  <div class="row align-items-center">
    <div class="col">
      One of three columns
    </div>
    <div class="col">
      One of three columns
    </div>
    <div class="col">
      One of three columns
    </div>
  </div>
  <div class="row align-items-end">
    <div class="col">
      One of three columns
    </div>
    <div class="col">
      One of three columns
    </div>
    <div class="col">
      One of three columns
    </div>
  </div>
</div>

One of three columns

<div class="container">
  <div class="row">
    <div class="col align-self-start">
      One of three columns
    </div>
    <div class="col align-self-center">
      One of three columns
    </div>
    <div class="col align-self-end">
      One of three columns
    </div>
  </div>
</div>

水平对齐

One of two columns

<div class="container">
  <div class="row justify-content-start">
    <div class="col-4">
      One of two columns
    </div>
    <div class="col-4">
      One of two columns
    </div>
  </div>
  <div class="row justify-content-center">
    <div class="col-4">
      One of two columns
    </div>
    <div class="col-4">
      One of two columns
    </div>
  </div>
  <div class="row justify-content-end">
    <div class="col-4">
      One of two columns
    </div>
    <div class="col-4">
      One of two columns
    </div>
  </div>
  <div class="row justify-content-around">
    <div class="col-4">
      One of two columns
    </div>
    <div class="col-4">
      One of two columns
    </div>
  </div>
  <div class="row justify-content-between">
    <div class="col-4">
      One of two columns
    </div>
    <div class="col-4">
      One of two columns
    </div>
  </div>
  <div class="row justify-content-evenly">
    <div class="col-4">
      One of two columns
    </div>
    <div class="col-4">
      One of two columns
    </div>
  </div>
</div>

列换行

如果单行中放置了超过 12 列，则超出的列所在组将作为一个单元整体换行。

.col-9

.col-4
由于 9 + 4 = 13 > 12 ，这个 4 列宽的 div 将作为一个整体单元换行。

.col-6
后续列沿新行继续。

<div class="container">
  <div class="row">
    <div class="col-9">.col-9</div>
    <div class="col-4">.col-4<br>Since 9 + 4 = 13 &gt; 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.</div>
    <div class="col-6">.col-6<br>Subsequent columns continue along the new line.</div>
  </div>
</div>

分栏

在 flexbox 中将列换行需要一个小技巧：添加一个 width: 100% 元素，无论您想将列换行到哪一行。通常这是通过多个 .row 来完成的，但并不是每个实现方法都可以解决这个问题。

.col-6 .col-sm-3

<div class="container">
  <div class="row">
    <div class="col-6 col-sm-3">.col-6 .col-sm-3</div>
    <div class="col-6 col-sm-3">.col-6 .col-sm-3</div>

    <!-- Force next columns to break to new line -->
    <div class="w-100"></div>

    <div class="col-6 col-sm-3">.col-6 .col-sm-3</div>
    <div class="col-6 col-sm-3">.col-6 .col-sm-3</div>
  </div>
</div>

您还可以使用我们的响应式显示实用程序在特定断点应用此中断。

.col-6 .col-sm-4

<div class="container">
  <div class="row">
    <div class="col-6 col-sm-4">.col-6 .col-sm-4</div>
    <div class="col-6 col-sm-4">.col-6 .col-sm-4</div>

    <!-- Force next columns to break to new line at md breakpoint and up -->
    <div class="w-100 d-none d-md-block"></div>

    <div class="col-6 col-sm-4">.col-6 .col-sm-4</div>
    <div class="col-6 col-sm-4">.col-6 .col-sm-4</div>
  </div>
</div>

排序

排序类

使用 .order- 类来控制内容的视觉顺序。这些类是响应式的，因此您可以通过断点设置 order（例如，.order-1.order-md-2）。包括对所有六个网格层的 1 到 5 的支持。

第一个 DOM 元素，没有应用排序

第二个 DOM 元素，排在第 5 位

第三个 DOM 元素，排在第 1 位

<div class="container">
  <div class="row">
    <div class="col">
      First in DOM, no order applied
    </div>
    <div class="col order-5">
      Second in DOM, with a larger order
    </div>
    <div class="col order-1">
      Third in DOM, with an order of 1
    </div>
  </div>
</div>

还有响应式类 .order-first 和 .order-last 分别通过应用 order：- 1 和 order: 6 来更改元素的 order 。这些类也可以根据需要与编号的 .order-* 类混合使用。

第一个 DOM 元素，排在末尾

第二个 DOM 元素，末排序

第三个 DOM 元素，排在开头

<div class="container">
  <div class="row">
    <div class="col order-last">
      First in DOM, ordered last
    </div>
    <div class="col">
      Second in DOM, unordered
    </div>
    <div class="col order-first">
      Third in DOM, ordered first
    </div>
  </div>
</div>

列偏移

您可以通过两种方式偏移网格列：我们的响应式 .offset- 网格类和我们的边距实用程序。网格类的大小与列匹配，而边距实用程序对于偏移宽度可变的快速布局更有用。

偏移类

使用 .offset-md-* 类将列向右移动。这些类将列的左边距增加 * 列。例如，.offset-md-4 将 .col-md-4 向右移动四列。

.col-md-4

.col-md-4 .offset-md-4

.col-md-3 .offset-md-3

.col-md-6 .offset-md-3

<div class="container">
  <div class="row">
    <div class="col-md-4">.col-md-4</div>
    <div class="col-md-4 offset-md-4">.col-md-4 .offset-md-4</div>
  </div>
  <div class="row">
    <div class="col-md-3 offset-md-3">.col-md-3 .offset-md-3</div>
    <div class="col-md-3 offset-md-3">.col-md-3 .offset-md-3</div>
  </div>
  <div class="row">
    <div class="col-md-6 offset-md-3">.col-md-6 .offset-md-3</div>
  </div>
</div>

除了在响应式断点处定义列偏移之外，您可能还需要重置偏移量。在网格示例中查看此操作。

.col-sm-5 .col-md-6

.col-sm-5 .offset-sm-2 .col-md-6 .offset-md-0

.col-sm-6 .col-md-5 .col-lg-6

.col-sm-6 .col-md-5 .offset-md-2 .col-lg-6 .offset-lg-0

<div class="container">
  <div class="row">
    <div class="col-sm-5 col-md-6">.col-sm-5 .col-md-6</div>
    <div class="col-sm-5 offset-sm-2 col-md-6 offset-md-0">.col-sm-5 .offset-sm-2 .col-md-6 .offset-md-0</div>
  </div>
  <div class="row">
    <div class="col-sm-6 col-md-5 col-lg-6">.col-sm-6 .col-md-5 .col-lg-6</div>
    <div class="col-sm-6 col-md-5 offset-md-2 col-lg-6 offset-lg-0">.col-sm-6 .col-md-5 .offset-md-2 .col-lg-6 .offset-lg-0</div>
  </div>
</div>

边距实用程序

在 v4 中迁移到 flexbox 后，您可以使用诸如 .me-auto 之类的边距实用程序来强制同级列彼此分离。

.col-md-4

.col-md-4 .ms-auto

.col-md-3 .ms-md-auto

.col-auto .me-auto

.col-auto

<div class="container">
  <div class="row">
    <div class="col-md-4">.col-md-4</div>
    <div class="col-md-4 ms-auto">.col-md-4 .ms-auto</div>
  </div>
  <div class="row">
    <div class="col-md-3 ms-md-auto">.col-md-3 .ms-md-auto</div>
    <div class="col-md-3 ms-md-auto">.col-md-3 .ms-md-auto</div>
  </div>
  <div class="row">
    <div class="col-auto me-auto">.col-auto .me-auto</div>
    <div class="col-auto">.col-auto</div>
  </div>
</div>

独立列类

.col-* 类也可以在 .row 之外使用，以赋予元素特定的宽度。每当列类用作行的非直接子级时，填充将被省略。

.col-3: width of 25%

.col-sm-9: width of 75% above sm breakpoint

<div class="col-3 bg-light p-3 border">
  .col-3: width of 25%
</div>
<div class="col-sm-9 bg-light p-3 border">
  .col-sm-9: width of 75% above sm breakpoint
</div>

这些类可以与实用程序一起使用来创建响应式浮动图片。如果文本较短，请确保将内容包围在具有 .clearfix 类的元素中以清除浮动。

A paragraph of placeholder text. We're using it here to show the use of the clearfix class. We're adding quite a few meaningless phrases here to demonstrate how the columns interact here with the floated image.

As you can see the paragraphs gracefully wrap around the floated image. Now imagine how this would look with some actual content in here, rather than just this boring placeholder text that goes on and on, but actually conveys no tangible information at. It simply takes up space and should not really be read.

And yet, here you are, still persevering in reading this placeholder text, hoping for some more insights, or some hidden easter egg of content. A joke, perhaps. Unfortunately, there's none of that here.

<div class="clearfix">
  <img src="..." class="col-md-6 float-md-end mb-3 ms-md-3" alt="...">

  <p>
    A paragraph of placeholder text. We're using it here to show the use of the clearfix class. We're adding quite a few meaningless phrases here to demonstrate how the columns interact here with the floated image.
  </p>

  <p>
    As you can see the paragraphs gracefully wrap around the floated image. Now imagine how this would look with some actual content in here, rather than just this boring placeholder text that goes on and on, but actually conveys no tangible information at. It simply takes up space and should not really be read.
  </p>

  <p>
    And yet, here you are, still persevering in reading this placeholder text, hoping for some more insights, or some hidden easter egg of content. A joke, perhaps. Unfortunately, there's none of that here.
  </p>
</div>