大家好日子，
我正在尝试制作来自“Menu2”的100％宽度水平下拉菜单。在“Menu2” - ＆gt;“SubMenu2”Iam尝试制作100％宽度水平下拉菜单SubSubMenu。有关最佳解决方案的任何想法吗？
非常感谢所有人的帮助。
body {
min-height: 2000px;
padding-top: 70px;
}
.navbar .navbar-nav {
display: inline-block;
float: none;
}
.navbar .navbar-collapse {
text-align: center;
}
.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 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:#cccccc;margin-top:5px;margin-right:-10px;}
.dropdown-submenu:hover>a:after{border-left-color:#ffffff;}
.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;}
@import url('http://getbootstrap.com/dist/css/bootstrap.css');
.dropdown > li{
display: inline-block;
float:center;
}
.open> ul {
display: inline-flex !important;
}<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<!-- The above 3 meta tags *must* come first in the head; any other head content must come *after* these tags -->
<meta name="description" content="">
<meta name="author" content="">
<link rel="icon" href="../../favicon.ico">
<title>Test</title>
<!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<!-- IE10 viewport hack for Surface/desktop Windows 8 bug -->
<link href="../../assets/css/ie10-viewport-bug-workaround.css" rel="stylesheet">
<!-- Custom styles for this template -->
<link href="style.css" rel="stylesheet">
<!-- Just for debugging purposes. Don't actually copy these 2 lines! -->
<!--[if lt IE 9]><script src="../../assets/js/ie8-responsive-file-warning.js"></script><![endif]-->
<script src="../../assets/js/ie-emulation-modes-warning.js"></script>
<!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->
<!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/html5shiv/3.7.3/html5shiv.min.js"></script>
<script src="https://oss.maxcdn.com/respond/1.4.2/respond.min.js"></script>
<![endif]-->
</head>
<body>
<!-- Fixed navbar -->
<nav class="navbar navbar-default navbar-fixed-top">
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">Logo</a>
</div>
<div id="navbar" class="navbar-collapse collapse">
<ul class="nav navbar-nav">
<li><a href="#about">Menu1</a></li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Menu2</a>
<ul class="dropdown-menu">
<li><a href="#">SubMenu1</a></li>
<li class="dropdown-submenu"><a href="#">SubMenu2</a>
<ul class="dropdown-menu">
<li><a href="#">SubSubMenu1</a></li>
<li><a href="#">SubSubMenu2</a></li>
<li><a href="#">SubSubMenu3</a></li>
</ul>
</li>
<li><a href="#">SubMenu3</a></li>
</ul>
</li>
<li><a href="#contact">Menu3</a></li>
</ul>
<ul class="nav navbar-nav navbar-right">
<li><a href="../navbar/">ENG</a></li>
<li><a href="../navbar/">LT</a></li>
</ul>
</div><!--/.nav-collapse -->
</div>
</nav>
<div class="container">
<!-- Main component for a primary marketing message or call to action -->
<div class="jumbotron">
<h1></h1>
<p></p>
<p></p>
<p>
<a class="btn btn-lg btn-primary" href="#" role="button">Button</a>
</p>
</div>
</div> <!-- /container -->
<!-- Bootstrap core JavaScript
================================================== -->
<!-- Placed at the end of the document so the pages load faster -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script>window.jQuery || document.write('<script src="../../assets/js/vendor/jquery.min.js"><\/script>')</script>
<!-- Latest compiled and minified JavaScript -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
<!-- IE10 viewport hack for Surface/desktop Windows 8 bug -->
<script src="../../assets/js/ie10-viewport-bug-workaround.js"></script>
</body>
</html>
答案 0 :(得分：0)
重点是禁用下拉列表position: relative并将其放在具有所需宽度的父级上：
#navbar {
position: relative;
}
#navbar .dropdown.has-container {
position: static;
}
#navbar .dropdown.has-container .dropdown-menu.container {
margin: 0 -15px;
}
<!-- ... -->
<li class="dropdown has-container">
<a href="#" class="dropdown-toggle"
data-toggle="dropdown" role="button"
aria-haspopup="true" aria-expanded="false">Menu2</a>
<ul class="dropdown-menu container">
<li><a href="#">SubMenu1</a></li>
<li class="dropdown-submenu"><a href="#">SubMenu2</a>
<!-- ... -->
概念证明： jsFiddle