У меня asp. net core mvc с использованием загрузочной коробки. Я заметил, что мое выпадающее меню не работает, я попробовал все, например, удаление файлов js и css и добавление их снова, но безуспешно, пока я не удалил загрузочную коробку. js и bom! и выпадающее меню работает нормально.
вот мой _Layout.cs html:
<!DOCTYPE html>
<html lang="ar-sa" dir="rtl">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>@ViewData["Title"] - POS3</title>
<script src="~/js/bootbox.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
<script src="~/lib/bootstrap/dist/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="~/lib/bootstrap/dist/css/bootstrap.min.css" />
<link rel="stylesheet" href="~/css/site.css" />
@*<script src="~/js/popper.min.js"></script>*@
</head>
<body>
<header>
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" asp-area="" asp-controller="Home" asp-action="Index">POS<sup>3</sup></a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target=".navbar-collapse" aria-controls="navbarSupportedContent"
aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<partial name="_LoginPartial" />
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Index">Home<span class="sr-only">(current)</span></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">
<a class="nav-link text-dark" asp-area="" asp-controller="SelectedItems" asp-action="POSMain">POSMain</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Products</a>
<ul class="dropdown-menu" aria-labelledby="navbarDropdown">
<il class="dropdown-item">
<a class="dropdown-item" asp-area="" asp-controller="Product" asp-action="Create">Add New Product</a>
</il>
</ul>
</li>
<li class="nav-item dropdown">
<ul class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
<li><a class="dropdown-item" href="#">Action</a></li>
<li><a class="dropdown-item" href="#">Another action</a></li>
<li class="dropdown-submenu">
<a class="dropdown-item dropdown-toggle" href="#">Submenu</a>
<ul class="dropdown-menu">
<li><a class="dropdown-item" href="#">Submenu action</a></li>
<li><a class="dropdown-item" href="#">Another submenu action</a></li>
<li class="dropdown-submenu">
<a class="dropdown-item dropdown-toggle" href="#">Subsubmenu</a>
<ul class="dropdown-menu">
<li><a class="dropdown-item" href="#">Subsubmenu action</a></li>
<li><a class="dropdown-item" href="#">Another subsubmenu action</a></li>
</ul>
</li>
<li class="dropdown-submenu">
<a class="dropdown-item dropdown-toggle" href="#">Second subsubmenu</a>
<ul class="dropdown-menu">
<li><a class="dropdown-item" href="#">Subsubmenu action</a></li>
<li><a class="dropdown-item" href="#">Another subsubmenu action</a></li>
</ul>
</ul>
</li>
</ul>
</li>
</ul>
<form class="form-inline my-2 my-lg-0">
<input class="form-control mr-sm-2" type="text" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
</header>
<div class="container" >
<main role="main" class="pb-3">
@RenderBody()
</main>
</div>
<footer class="border-top footer text-muted">
<div class="container">
© 2019 - POS3 - <a asp-area="" asp-controller="Home" asp-action="Privacy">Privacy</a>
</div>
</footer>
<script src="~/lib/jquery/dist/jquery-3.3.1.js"></script>
<script src="~/lib/jquery/dist/jquery.js"></script>
<script src="~/js/jquery.dataTables.min.js"></script>
<script src="~/js/DataTables/jquery.dataTables.min.js" defer></script>
<script src="~/lib/jquery/dist/jquery.min.js"></script>
<script src="~/lib/bootstrap/dist/js/bootstrap.bundle.min.js"></script>
<script src="~/js/site.js" asp-append-version="true"></script>
@RenderSection("Scripts", required: false)
@RenderSection("Menu", required: false)
@RenderSection("ProductScript", false)
</body>
</html>
я думаю, что-то есть в загрузочной коробке. js просто останавливает раскрывающийся список, чтобы работать как обычно.