css - 使用 bootstrap 的垂直主菜单的水平子菜单

Question

有没有办法使用 Bootstrap 为垂直菜单结构创建水平子菜单我还没有看到任何具有垂直主菜单方向的子菜单。菜单结构的示例结构类似于此

Answer 1

我们来了!

下拉菜单可以使用嵌套的“ul”、绝对位置，并且我们将从 display: none; 更改为 display:block;需要悬停。

类似这样的事情:

<ul>
  <li><a href="#">…</a>
    <ul>
      <li><a href="#">…</a>
        <ul> … <!-- And so on. -->
        </ul>
      </li>
  <li>
</ul>

您的示例的 html

<nav id="main-nav">
  <ul>
    <li><a href="#">Home</a></li>
    <li><a href="#">About</a></li>
    <li><a href="#">Projects</a>
      <ul>
        <li><a href="#">Project 1</a>
          <ul>
            <li><a href="#">Project 2</a>
              <ul>
                <li><a href="#">Project 3</a>
                  <ul>
                    <li><a href="#">Project 4</a>
                      <ul>
                        <li><a href="#">Project 5</a></li>
                      </ul>
                    </li>
                  </ul>
                </li>
              </ul>
            </li>
          </ul>
        </li>
      </ul>
    </li>
    <li><a href="#">Contact</a></li>
  </ul>
</nav>

你的explame的SCSS:(我使用了sass，因为它更容易阅读和编写，但我也会在下面粘贴CSS)

#main-nav{
  ul{ /* Those lines are used only for styling */
    margin: 0;
    padding: 0;
    border-right: 1px solid black;
    width: 150px;
    list-style-type: none;
    li{
      position: relative; /* This is important when using absolute positions. */
      &:hover{
        &:before{ /* arrow styles */
              content: "";
              top: 0;
              bottom: 0;
              right: 0;
              border-top: 5px solid transparent;
              border-right: 5px solid #999;
              border-bottom: 5px solid transparent;
              border-left: 5px solid transparent;
              position: absolute;
              height: 0px;
              width: 0px;
              margin: auto;
        }
        > ul{
          display: block; /* IMPORTANT: This will show your dropdown menus when hover in the parent li. */

          /*&:before { // I don't like this part but if you enable it, it will make child ul's look closer to your design.
              content: "";
              position: absolute;
              right: 0;
              top: -65px;
              bottom: -35px;
              width: 1px;
              background-color: #ccc;
          }*/
        }
      }//:hover

      a{ /* Those lines are used only for styling */
        padding: 7px 10px;
        display: block;
        &:hover{
          color: red;
        }
      }// a

      > ul{ /* This is what makes the magic happen. */
        display: none; /* Dropdown menus are always hidden, except when you hover it's li parent */
        position: absolute; /* This will position the ul */
        top: 0;
        left: 100%; /* This will push the ul where it is needed. */
        border-right: 1px solid #ccc;
      }
    }// li
  }// ul
}

实例:https://jsfiddle.net/xwazzo/3spxxk1z/

以及 promise 的 CSS 版本:

#main-nav ul {
  margin: 0;
  padding: 0;
  border-right: 1px solid black;
  width: 150px;
  list-style-type: none; 
}

#main-nav ul li { position: relative; }
#main-nav ul li:hover:before {
  content: "";
  top: 0;
  bottom: 0;
  right: 0;
  border-top: 5px solid transparent;
  border-right: 5px solid #999;
  border-bottom: 5px solid transparent;
  border-left: 5px solid transparent;
  position: absolute;
  height: 0px;
  width: 0px;
  margin: auto; 
}

#main-nav ul li:hover > ul { display: block; }
#main-nav ul li a {
  padding: 7px 10px;
  display: block; 
}

#main-nav ul li a:hover { color: red; }
#main-nav ul li > ul {
  display: none;
  position: absolute;
  top: 0;
  left: 100%;
  border-right: 1px solid #ccc; 
}