Bootstrap 4 在右側顯示下拉子菜單

Question

我在 Bootstrap 4 中創建了一個多級下拉菜單。我想在父下拉菜單的右側顯示下拉子菜單。 我已將菜單向右對齊，但這不是我想要的。 如何在右側顯示下拉子菜單而不是右對齊？

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script> <link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet" /> <nav class="navbar navbar-custom navbar-expand-md bg-dark navbar-dark"> <button class="navbar-toggler" data-toggle="collapse" data-target="#collapse_target"> <span class="navbar-toggler-icon"></span> </button> <div class="collapse navbar-collapse" id="collapse_target"> <ul class="navbar-nav"> <li class="nav-item dropdown"> <a class="nav-link" data-toggle="dropdown" data-target="#dropdown_target" href="#"> DEPARTMENTS </a> <ul class="dropdown-menu" aria-labelledby="dropdown_target"> <li class="dropdown-item dropdown"> <a data-toggle="dropdown" data-target="#auto_en" href="#">Automobile Engineering</a> <ul class="dropdown-menu dropdown-menu-right" aria-labelledby="auto_en"> <li class="dropdown-item"><a href="#">HOD's Desk</a> </li> <li class="dropdown-item"><a href="#">About Us</a></li> <li class="dropdown-item"><a href="#">Faculty</a></li> <li class="dropdown-item"><a href="#">Events</a></li> <li class="dropdown-item"><a href="#">Class Timetable</a></li> <li class="dropdown-item"><a href="#">Results</a></li> </ul> </li> </ul> </li> </ul> </div> </nav>

在這里，汽車工程的子菜單是 -HOD's Desk -About Us -Faculty.... 我希望這個子菜單顯示在包含汽車工程的父子菜單的右側。

我使用了 dropdown-menu-right bootstrap 類，但這會將菜單向右對齊，並且不會在父菜單之外顯示它。

謝謝。

Answer 1

將左添加到要更改其位置的下拉菜單。 如下圖所示

.dropdown-menu.show.abc {
  left: 95%;
}

 .dropdown-menu.show.abc { left: 95%; top: 20px; }

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script> <link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet" /> <nav class="navbar navbar-custom navbar-expand-md bg-dark navbar-dark"> <button class="navbar-toggler" data-toggle="collapse" data-target="#collapse_target"> <span class="navbar-toggler-icon"></span> </button> <div class="collapse navbar-collapse" id="collapse_target"> <ul class="navbar-nav"> <li class="nav-item dropdown"> <a class="nav-link" data-toggle="dropdown" data-target="#dropdown_target" href="#"> DEPARTMENTS </a> <ul class="dropdown-menu abc" aria-labelledby="dropdown_target"> <li class="dropdown-item dropdown"> <a data-toggle="dropdown" data-target="#auto_en" href="#">Automobile Engineering</a> <ul class="dropdown-menu dropdown-menu-right" aria-labelledby="auto_en"> <li class="dropdown-item"><a href="#">HOD's Desk</a> </li> <li class="dropdown-item"><a href="#">About Us</a></li> <li class="dropdown-item"><a href="#">Faculty</a></li> <li class="dropdown-item"><a href="#">Events</a></li> <li class="dropdown-item"><a href="#">Class Timetable</a></li> <li class="dropdown-item"><a href="#">Results</a></li> </ul> </li> </ul> </li> </ul> </div> </nav>

Answer 2

  .navbar-expand-md .navbar-nav .dropdown-menu {
        position: absolute;
        top: -7px;
        right: auto;
        left: 100%;
    }

Answer 3

我認為這就是你要找的https://codepen.io/svnt/pen/beEgre

HTML：

<div class="container">
    <div class="row">
        <h2>Multi level dropdown menu in Bootstrap</h2>
        <hr>
        <div class="dropdown">
            <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
              Dropdown
            </button>
            <ul class="dropdown-menu multi-level" role="menu" aria-labelledby="dropdownMenu">
                <li class="dropdown-item"><a href="#">Some action</a></li>
                <li class="dropdown-item"><a href="#">Some other action</a></li>
                <li class="dropdown-divider"></li>
                <li class="dropdown-submenu">
                  <a  class="dropdown-item" tabindex="-1" href="#">Hover me for more options</a>
                  <ul class="dropdown-menu">
                    <li class="dropdown-item"><a tabindex="-1" href="#">Second level</a></li>
                    <li class="dropdown-submenu">
                      <a class="dropdown-item" href="#">Even More..</a>
                      <ul class="dropdown-menu">
                          <li class="dropdown-item"><a href="#">3rd level</a></li>
                            <li class="dropdown-submenu"><a class="dropdown-item" href="#">another level</a>
                            <ul class="dropdown-menu">
                                <li class="dropdown-item"><a href="#">4th level</a></li>
                                <li class="dropdown-item"><a href="#">4th level</a></li>
                                <li class="dropdown-item"><a href="#">4th level</a></li>
                            </ul>
                          </li>
                            <li class="dropdown-item"><a href="#">3rd level</a></li>
                      </ul>
                    </li>
                    <li class="dropdown-item"><a href="#">Second level</a></li>
                    <li class="dropdown-item"><a href="#">Second level</a></li>
                  </ul>
                </li>
              </ul>
        </div>
    </div>
</div>

CSS：

.dropdown-submenu {
    position: relative;
}

.dropdown-submenu>.dropdown-menu {
    top: 0;
    left: 100%;
    margin-top: -6px;
    margin-left: -1px;
    -webkit-border-radius: 0 6px 6px 6px;
    -moz-border-radius: 0 6px 6px;
    border-radius: 0 6px 6px 6px;
}

.dropdown-submenu:hover>.dropdown-menu {
    display: block;
}

.dropdown-submenu>a:after {
    display: block;
    content: " ";
    float: right;
    width: 0;
    height: 0;
    border-color: transparent;
    border-style: solid;
    border-width: 5px 0 5px 5px;
    border-left-color: #ccc;
    margin-top: 5px;
    margin-right: -10px;
}

.dropdown-submenu:hover>a:after {
    border-left-color: #fff;
}

.dropdown-submenu.pull-left {
    float: none;
}

.dropdown-submenu.pull-left>.dropdown-menu {
    left: -100%;
    margin-left: 10px;
    -webkit-border-radius: 6px 0 6px 6px;
    -moz-border-radius: 6px 0 6px 6px;
    border-radius: 6px 0 6px 6px;
}

注意：代碼不是我的。