下拉菜单中的 Bootstrap4 下拉菜单关闭父菜单

Question

我在一个下拉菜单中有一个下拉菜单“F”，单击它时我需要展开它。现在它做了一些奇怪的事情——它关闭了父菜单（下拉菜单）。此外，当明确表示不应该扩展时，默认情况下会扩展下拉菜单。

找不到任何关于我的问题的信息，所以我请求您的帮助。

这是发生的事情的 gif 图像。

重现此的代码如下：

<ul class="navbar-nav flex-grow-1">
    <li class="nav-item">
        <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Index">Home</a>
    </li>
    <li class="nav-item">
        <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Privacy">Privacy</a>
    </li>

    <li class="nav-item">
        <div class="nav-item dropdown">
            <a class="nav-link dropdown-toggle" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                Operations
            </a>
            <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
                <a class="dropdown-item" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">A</a>
                <a class="dropdown-item" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">B</a>
                <a class="dropdown-item" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">C</a>
                <a class="dropdown-item" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">D</a>
                <a class="dropdown-item" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">E</a>

                <div class="dropright">
                    <a class="dropdown-toggle nav-link" id="navbarDropdownMenuLink2" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                        F
                    </a>
                    <div class="dropdown-submenu" aria-labelledby="navbarDropdownMenuLink2">
                        <a class="dropdown-item" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">F1</a>
                        <a class="dropdown-item" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">F2</a>
                    </div>
                </div>
            </div>
        </div>
    </li>
</ul>

提前谢谢你！

Answer 1

嵌套下拉菜单需要一些 JavaScript；没有dropdown-submenu 类；看看下面的代码是否能得到你想要的......

$(document).ready(function() {
  $('.dropdown-menu a.dropdown-toggle').on('click', function(e) {
    if (!$(this).next().hasClass('show')) {
      $(this).parents('.dropdown-menu').first().find('.show').removeClass("show");
    }
    var $subMenu = $(this).next(".dropdown-menu");
    $subMenu.toggleClass('show');


    $(this).parents('li.nav-item.dropdown.show').on('hidden.bs.dropdown', function(e) {
      $('.dropdown-submenu .show').removeClass("show");
    });

    return false;
  });
});

.dropdown-submenu {
  position: relative;
}

.dropdown-submenu a::after {
  transform: rotate(-90deg);
  position: absolute;
  right: 6px;
  top: .8em;
}

.dropdown-submenu .dropdown-menu {
  top: 0;
  left: 100%;
  margin-left: .1rem;
  margin-right: .1rem;
}

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/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://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>

<nav class="navbar navbar-expand-sm navbar-light bg-light">
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarTogglerDemo01" aria-controls="navbarTogglerDemo01" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="navbarTogglerDemo01">
    <a class="navbar-brand" href="#">Home</a>
    <ul class="navbar-nav mr-auto mt-2 mt-lg-0">
      <li class="nav-item active">
        <a class="nav-link" href="#">Privacy</a>
      </li>

      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Operations
        </a>
        <ul class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
          <li><a class="dropdown-item" href="#" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">A</a></li>
          <li><a class="dropdown-item" href="#" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">B</a></li>
          <li><a class="dropdown-item" href="#" asp-area=" " asp-controller=" " asp-action=" " asp-route-companyId=" ">C</a></li>
          <li><a class="dropdown-item" href="#" asp-area=" " asp-controller=" " asp-action=" " asp-route-companyId=" ">D</a></li>
          <li><a class="dropdown-item" href="#" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">E</a></li>

          <li class="dropdown-submenu"><a class="dropdown-item dropdown-toggle" href="#">F</a>
            <ul class="dropdown-menu">
              <li><a class="dropdown-item" href="#" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">F1</a></li>
              <li><a class="dropdown-item" href="#" asp-area="" asp-controller="" asp-action="" asp-route-companyId="">F2</a></li>

            </ul>
          </li>
        </ul>
      </li>
    </ul>

  </div>
</nav>