我正在为一项作业构建一个网站，讲师根据 https://learn.microsoft.com/en-us/aspnet/web-pages/overview/ui-layouts-and-themes/3-creating-a-consistent-look 向我们展示了如何使用 _header、_footer 和 _layout|
在我向 _header.cshtml 中的导航栏添加下拉菜单之前，一切都很好。当我的网站使用普通的 HTML 和 CSS 时，它工作正常。但是，一旦我将新布局添加到其中，下拉菜单将不起作用。
_Layout.cshtml:
<!DOCTYPE html>
<html>
<head>
<title>@Page.Title</title>
@RenderSection("head", required: false)
</head>
<body>
@RenderPage("~/shared/_header.cshtml")
@RenderBody()
@RenderPage("~/shared/_footer.cshtml")
</body>
</html>
_Header.cshtml:
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link href="~/css/bootstrap.css" rel="stylesheet" />
<link href="~/css/bootstrap.min.css" rel="stylesheet" />
<link href="~/css/Site.css" rel="stylesheet" />
<link href="~/css/viewImg.css" rel="stylesheet" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>
<nav class="navbar navbar-inverse">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle " 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="#">VPC</a>
</div>
<div id="navbar" class="navbar-collapse collapse">
<ul class="nav navbar-nav">
<li><a href="~/index.cshtml">Home</a></li>
<li><a href="~/About.cshtml">About</a></li>
<li><a href="~/Contact.cshtml">Contact</a></li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">More <span class="caret"></span></a>
<ul class="dropdown-menu">
<li><a href="~/Cameras.cshtml">Cameras</a></li>
<li><a href="~/Photography.cshtml">Photography</a></li>
<li><a href="~/Videography.cshtml">Videography</a></li>
</ul>
</li>
</ul>
<ul class="nav navbar-nav navbar-right">
<li class="active">
<a href="~/Login.cshtml">
<img class="signin-img" src="~/img/signin.png" width="26" height="26"/>
</a>
</li>
</ul>
</div><!--/.nav-collapse -->
</div><!--/.container-fluid -->
</nav>
</body>
</html>
index.cshtml:(这是主页)
@{
Page.Title = "Title goes here";
Layout = "~/shared/_Layout.cshtml";
//Layout = "Your Layout Page goes here";
}
<div class="container">
<div class="jumbotron" style="background-image: url(img/vpc_main.jpg); background-size: 100%; opacity: 0.6;">
<h1 style="color: #ffffff; text-align: center; opacity: 2;">Video Photography Camera</h1>
</div>
</div>
<div class="container">
<div class="row">
<div class="col-sm-4">
<section>
<img class="img-responsive" src="img/cameras.jpg" />
<h1 class="wtext">Cameras</h1>
<p class="wtext">
Search our catalog which includes the best cameras on the market. From DSLR to Mirrorless.
</p>
<a class="btn btn-default form-control" href="cameras.cshtml">Go To ></a>
</section>
</div>
<div class="col-sm-4">
<section>
<img class="img-responsive" src="img/photography.jpg" />
<h1 class="wtext">Photography</h1>
<p class="wtext">
Search our catalog of pictures that ranges from nature to portrait photography.
</p>
<a class="btn btn-default form-control" href="photography.cshtml">Go to ></a>
</section>
</div>
<div class="col-sm-4">
<section>
<img class="img-responsive" src="img/videography.jpg" />
<h1 class="wtext">Videography</h1>
<p class="wtext">
Search our catalog of videos that vary from montage to action videography.
</p>
<a class="btn btn-default form-control" href="videography.cshtml">Go to ></a>
</section>
</div>
</div>
<div class="container-fluid">
</div>
<br /><br />
</div>
Cameras.cshtml:(这是我不想使用下拉菜单重定向到的页面)
@{
Page.Title = "Title goes here";
Layout = "~/shared/_Layout.cshtml";
}
<div class="container">
<br />
<h1>Cameras</h1>
<div class="row">
<div class="col-lg-3" style="border-right: 1px solid #000000; height: 600px;">
<h3 style="text-align: center"><a href="https://www.sony.com/electronics/interchangeable-lens-camera-products/t/interchangeable-lens-cameras?bestfor=advanced-amateur">Sony ></a></h3>
<h3 style="text-align: center"><a href="https://www.usa.canon.com/internet/portal/us/home/products/list/cameras/dslr/">Canon ></a></h3>
<h3 style="text-align: center"><a href="http://imaging.nikon.com/lineup/dslr/index.htm">Nikon ></a></h3>
</div>
<div class="col-lg-3">
<h2 style="text-align: center">Sony</h2>
<br />
<div class="imgcontainer">
<img src="img/Cameras/sony_a7RIII.jpg" width="240" alt="A7R Mark III" class="image" />
<div class="imgoverlay" onclick="location.href = 'https://www.sony.com/electronics/interchangeable-lens-cameras/ilce-7rm3'">
<div class="imgtext">A7R Mark III</div>
</div>
</div>
<br />
<div class="imgcontainer">
<img src="img/Cameras/sony_a6500.jpg" width="240" alt="a6500" class="image" />
<div class="imgoverlay" onclick="location.href = 'https://www.sony.com/electronics/interchangeable-lens-cameras/ilce-6500-body-kit'">
<div class="imgtext">a6500</div>
</div>
</div>
<br />
<div class="imgcontainer">
<img src="img/Cameras/sony_rx100mkV.jpg" width="240" alt="rx100mk Mark V" class="image" />
<div class="imgoverlay" onclick="location.href = 'https://www.sony.com/electronics/cyber-shot-compact-cameras/dsc-rx100m5'">
<div class="imgtext">rx100mk Mark V</div>
</div>
</div>
<br />
</div>
<div class="col-lg-3">
<h2 style="text-align: center">Canon</h2>
<br />
<div class="imgcontainer">
<img src="img/Cameras/canon_1dX.jpg" width="240" alt="1D X" class="image" />
<div class="imgoverlay" onclick="location.href = 'https://www.usa.canon.com/internet/portal/us/home/products/details/cameras/dslr/eos-1d-x'">
<div class="imgtext">1D X</div>
</div>
</div>
<br />
<div class="imgcontainer">
<img src="img/Cameras/canon_6dII.jpg" width="240" alt="6D Mark II" class="image" />
<div class="imgoverlay" onclick="location.href = 'https://www.usa.canon.com/internet/portal/us/home/products/details/cameras/dslr/eos-6d-mark-ii'">
<div class="imgtext">6D Mark II</div>
</div>
</div>
<br />
<div class="imgcontainer">
<img src="img/Cameras/canon_rebelt6i.jpg" width="240" alt="Rebel t6i" class="image" />
<div class="imgoverlay" onclick="location.href = 'https://www.usa.canon.com/internet/portal/us/home/products/details/cameras/dslr/eos-rebel-t6i-ef-s-18-55mm-is-stm'">
<div class="imgtext">Rebel t6i</div>
</div>
</div>
<br />
</div>
<div class="col-lg-3">
<h2 style="text-align: center">Nikon</h2>
<br />
<div class="imgcontainer">
<img src="img/Cameras/nikon_d5.jpg" width="240" alt="D5" class="image" />
<div class="imgoverlay" onclick="location.href = 'https://www.nikonusa.com/en/nikon-products/product/dslr-cameras/d5.html'">
<div class="imgtext">D5</div>
</div>
</div>
<br />
<div class="imgcontainer">
<img src="img/Cameras/nikon_d800.jpg" width="240" alt="D810" class="image" />
<div class="imgoverlay" onclick="location.href = 'https://www.nikonusa.com/en/nikon-products/product/dslr-cameras/d810.html'">
<div class="imgtext">D810</div>
</div>
</div>
<br />
<div class="imgcontainer">
<img src="img/Cameras/nikon_d810.jpg" width="240" alt="D3400" class="image" />
<div class="imgoverlay" onclick="location.href = 'https://www.nikonusa.com/en/nikon-products/product/dslr-cameras/d3400.html'">
<div class="imgtext">D3400</div>
</div>
</div>
<br />
</div>
</div>
<div>
</div>
</div>
site.css(自定义样式表)
body {
padding-top: 50px;
padding-bottom: 20px;
/*background-image: url('../img/computer-programming-background-1461985468sGF.jpg');*/
background-image: url(../img/background02.jpg);
}
.navbar {
padding: 0;
border: 0;
}
/* Wrapping element */
/* Set some basic padding to keep content from hitting the edges */
.body-content {
padding-left: 15px;
padding-right: 15px;
}
/* Set widths on the form inputs since otherwise they're 100% wide */
input,
select,
textarea {
max-width: 280px;
}
/* Responsive: Portrait tablets and up */
@media screen and (min-width: 768px) {
.jumbotron {
margin-top: 10px;
}
.body-content {
padding: 0;
}
}
@keyframes pics {
0% {
transform: rotate(0deg);
}
100% {
transform: rotate(360deg);
}
}
.img-effect {
animation: pics 10s infinite;
animation-play-state: paused;
}
.img-effect:hover {
animation: pics 10s infinite;
animation-play-state: running;
}
/* login and signup */
.login-container {
position: center;
}
/* overide button color: */
.btn-default {
color: #cccccc;
/*background-color: #333333;
border-color: #cccccc;*/
opacity: 0.8;
background-image: url(../img/btn02_img.jpg);
background-size: 100%;
text-align: center;
}
.btn-default:hover,
.btn-default:focus,
.btn-default:active,
.btn-default.active,
.open .dropdown-toggle.btn-default {
color: #adadad;
/*background-color: #cccccc;
border-color: #adadad;
background-image: url(../img/btn01_img.jpg);*/
opacity: 1;
background-size: 100%;
text-align: center;
}
/* Custom Glyphicons for sign in and sign out*/
.signin-img {
filter: invert(100%);
}
/* style the container */
.container {
background: rgba( 192, 192, 192, 0.3 );
}
.wtext {
color: #ffffff;
}
viewImg.css:(Cameras.cshtml 的样式表)
.imgcontainer {
position: relative;
width: 91.5%;
}
.image {
display: block;
width: 240px;
height: auto;
}
.imgoverlay {
position: absolute;
top: 0;
bottom: 0;
left: 0;
right: 0;
height: 100%;
width: 100%;
opacity: 0;
transition: .5s ease;
background-color: #000000;
}
.imgcontainer:hover .imgoverlay {
opacity: 0.8;
cursor: pointer;
}
.imgtext {
color: white;
font-size: 20px;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
-ms-transform: translate(-50%, -50%);
text-align: center;
}
This is the Picture of the Home Webpage
基本上，我的问题是:为什么下拉菜单不起作用，有没有办法解决它？ (在图片中，下拉菜单位于导航栏的左侧)。
最佳答案
为什么要包含 Bootstrap 3 次？开始单独注释掉这些，看看它是否有所作为，并在每次测试时进行完整的浏览器刷新。
此外，将它们移动到布局文件中，以便它们影响所有 View 。
关于html - Bootstrap 下拉菜单不显示，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/49000605/