这可能会有帮助:

$("dropdownmenuname").click(function(e){
   e.stopPropagation();
})

比如Bootstrap 4 Alpha有这个菜单事件。为什么不用呢?

// PREVENT INSIDE MEGA DROPDOWN
$('.dropdown-menu').on("click.bs.dropdown", function (e) {
    e.stopPropagation();
    e.preventDefault();                
});

我还找到了一个解决办法。

假设Twitter Bootstrap Components相关事件处理程序被委托给文档对象，我循环所附的处理程序，并检查当前单击的元素(或其父元素之一)是否与委托的事件有关。

$('ul.dropdown-menu.mega-dropdown-menu').on('click', function(event){
    var events = $._data(document, 'events') || {};
    events = events.click || [];
    for(var i = 0; i < events.length; i++) {
        if(events[i].selector) {

            //Check if the clicked element matches the event selector
            if($(event.target).is(events[i].selector)) {
                events[i].handler.call(event.target, event);
            }

            // Check if any of the clicked element parents matches the 
            // delegated event selector (Emulating propagation)
            $(event.target).parents(events[i].selector).each(function(){
                events[i].handler.call(this, event);
            });
        }
    }
    event.stopPropagation(); //Always stop propagation
});

希望它能帮助任何寻求类似解决方案的人。

谢谢大家的帮助。

演示:http://jsfiddle.net/4y8tLgcp/

$('ul.nav.navbar-nav').on('click.bs.dropdown', function(e){
    var $a  = $(e.target), is_a = $a.is('.is_a');
    if($a.hasClass('dropdown-toggle')){   
        $('ul.dropdown-menu', this).toggle(!is_a);
        $a.toggleClass('is_a', !is_a);
    }
}).on('mouseleave', function(){
    $('ul.dropdown-menu',this).hide();
    $('.is_a', this).removeClass('is_a');
});

我再次更新了它，使之尽可能的聪明和实用。它现在关闭时，你悬停在导航之外，保持开放，而你是在里面。简单的完美。

你也可以使用表单标签。例子:

<div class="dropdown-menu">
    <form>
        Anything inside this wont close the dropdown!
        <button class="btn btn-primary" type="button" value="Click me!"/>
    </form>
    <div class="dropdown-divider"></div>
    <a class="dropdown-item" href="#">Clik this and the dropdown will be closed</a>
    <a class="dropdown-item" href="#">This too</a>
</div>

来源:https://getbootstrap.com/docs/5.0/components/dropdowns/形式

引导4

$('.dropdown-menu[data-handledropdownclose="true"]').on("click.bs.dropdown", function (e) {
    if ($(this).parent().hasClass("show")) {
        var target = $(e.target);

        if (!(target.hasClass("CloseDropDown") || target.parents(".CloseDropDown").length)) {
            e.stopPropagation();
        }
    }
});

<div class="dropdown">
    <button type="button" class="btn-no-border dropdown-toggle" data-toggle="dropdown">
        <img src="~/Content/CSS/CssImages/Icons/usr_icon.png" alt="" title="language" class="float-right" />
    </button>

    <div class="dropdown-menu profile-menu-logout" data-handledropdownclose="true">
        <div class="prof-name">
            <i class="fa fa-user"></i> Hello World
        </div>

        <hr />

        <div>
            <a href="/Test/TestAction" class="CloseDropDown">
                <i class="fa fa-briefcase"></i>
                <span>Test Action</span>
            </a>
        </div>

        <div>
            <nav>
                <ul class="nav-menu-prof padding-0">
                    <li class="menu-has-children">
                        <a href="#">
                            <span class="cyan-text-color">
                                Test 2
                            </span>
                        </a>

                        <ul id="ulList" class="padding-0 pad-left-25">
                            <li>
                                <a href="/Test/Test2" class="action currentmenu"> Test 1 </a>
                                <a href="/Test/Test2" class="action CloseDropDown"> Test 2 </a>
                            </li>
                        </ul>
                    </li>
                </ul>
            </nav>
        </div>

        <div>
            <a href="/Account/Logout" class="cyan-text-color CloseDropDown">
                <i class="fa fa-power-off"></i>
                <span>Logout</span>
            </a>
        </div>
    </div>
</div>