If you have started developing web applications with ASP .NET MVC 5 you might have noticed that it comes with bootstrap version 2 and the latest version 3. In order to upgrade the default template for version 3, you can use these files as a reference.

Right click solution -> Manage NuGet packages Updates -> Update bootstrap to version 3 >

***Views/Shared/_Layout.cshtml***

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>@ViewBag.Title - My ASP.NET Application</title>
    @Styles.Render("~/Content/css")
    @Scripts.Render("~/bundles/modernizr")
</head>
<body>
    <div class="navbar navbar-default navbar-static-top">
        <div class="container">
            <div class="navbar-header">
                <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
                @Html.ActionLink("Application name", "Index", "Home", null, new { @class = "navbar-brand" })
            </div>
                           @Html.Partial("_LoginPartial")
            <div class="navbar-collapse collapse">
                <ul class="nav navbar-nav">
                    <li class="active">@Html.ActionLink("Home", "Index", "Home")</li>
                    <li>@Html.ActionLink("About", "About", "Home")</li>
                    <li>@Html.ActionLink("Contact", "Contact", "Home")</li>
                    <li class="dropdown">
                        <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown <b class="caret"></b></a>
                        <ul class="dropdown-menu">
                            <li><a href="#">Action</a></li>
                            <li><a href="#">Another action</a></li>
                            <li><a href="#">Something else here</a></li>
                            <li class="divider"></li>
                            <li class="dropdown-header">Nav header</li>
                            <li><a href="#">Separated link</a></li>
                            <li><a href="#">One more separated link</a></li>
                        </ul>
                    </li>
                </ul>
            </div><!--/.nav-collapse -->
        </div>
    </div>
    <div class="container">
        @RenderBody()
        <hr />
        <footer>
            <p>&copy; @DateTime.Now.Year - My ASP.NET Application</p>
        </footer>
    </div>
    @Scripts.Render("~/bundles/jquery")
    @Scripts.Render("~/bundles/bootstrap")
    @RenderSection("scripts", required: false)
</body>
</html>

 

***Views/Shared/_LoginPartial.cshtml***

@using Microsoft.AspNet.Identity
@if (Request.IsAuthenticated)
{
    using (Html.BeginForm("LogOff", "Account", FormMethod.Post, new { id = "logoutForm", @class = "navbar-form pull-right" }))
    {
    @Html.AntiForgeryToken()
    <ul class="nav navbar-nav navbar-right">
        <li>
            @Html.ActionLink("Hello " + User.Identity.GetUserName() + "!", "Manage", "Account", routeValues: null, htmlAttributes: new { title = "Manage" })
        </li>
        <li><a href="javascript:document.getElementById('logoutForm').submit()">Log off</a></li>
    </ul>
    }
}
else
{
    <ul class="nav navbar-nav navbar-right">
        <li>@Html.ActionLink("Register", "Register", "Account", routeValues: null, htmlAttributes: new { id
= "registerLink" })</li>
        <li>@Html.ActionLink("Log in", "Login", "Account", routeValues: null, htmlAttributes: new { id =
"loginLink" })</li>
    </ul>
}