ASP.NET Core 5.0 MVC中的视图分类及使用——布局视图、启动视图、导入视图、详细视图、分部视图

        </h1>
        <div class="clear"></div>
        <div class="postBody">

创建MVC应用程序

创建后的项目

启动视图 _ViewStart.cshtml

顾名思义，就是在View开始执行之前执行，而且是每一个View, 它的预设内容是

@{
    Layout = "_Layout";
}

我们可以在这个页面，添加一些全局性的内容，比如全局变量等，然后在具体View页面使用这些变量值

导入视图_ViewImports.cshtml，

它的作用是放一些要引用的命名空间，之后的每一个View就不用再引用这些命名空间了，_ViewImports.cshtml一样。它的预设内容是

@using net5MVC
@using net5MVC.Models
@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers

在这个页面，我们根据页面需要去引用命名空间，它的作用范围是全局的。在这个页面添加文本是没有效果的。

布局视图_Layout.cshtml

它的作用是让所有的视图页保持一致的外观，比如说统一的左侧目录、统一的头部导航、头部轮廓图、统一底部官网链接等。它的预设内容是

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>@ViewData["Title"] - net5MVC</title>
    <link rel="stylesheet" href="~/lib/bootstrap/dist/css/bootstrap.min.css" />
    <link rel="stylesheet" href="~/css/site.css" />
</head>
<body>
    <header>
        <nav class="navbar navbar-expand-sm navbar-toggleable-sm navbar-light bg-white border-bottom box-shadow mb-3">
            <div class="container">
                <a class="navbar-brand" asp-area="" asp-controller="Home" asp-action="Index">net5MVC</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="navbar-collapse collapse d-sm-inline-flex justify-content-between">
                    <ul class="navbar-nav flex-grow-1">
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Index">Home</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Privacy">Privacy</a>
                        </li>
                    </ul>
                </div>
            </div>
        </nav>
    </header>
    <div class="container">
        <main role="main" class="pb-3">
            @RenderBody()
        </main>
    </div>
&lt;footer <span style="color: rgba(0, 0, 255, 1)">class</span>=<span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">border-top footer text-muted</span><span style="color: rgba(128, 0, 0, 1)">"</span>&gt;
    &lt;div <span style="color: rgba(0, 0, 255, 1)">class</span>=<span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">container</span><span style="color: rgba(128, 0, 0, 1)">"</span>&gt;
        &amp;copy; <span style="color: rgba(128, 0, 128, 1)">2021</span> - net5MVC - &lt;a asp-area=<span style="color: rgba(128, 0, 0, 1)">""</span> asp-controller=<span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">Home</span><span style="color: rgba(128, 0, 0, 1)">"</span> asp-action=<span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">Privacy</span><span style="color: rgba(128, 0, 0, 1)">"</span>&gt;Privacy&lt;/a&gt;
    &lt;/div&gt;
&lt;/footer&gt;
&lt;script src=<span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">~/lib/jquery/dist/jquery.min.js</span><span style="color: rgba(128, 0, 0, 1)">"</span>&gt;&lt;/script&gt;
&lt;script src=<span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">~/lib/bootstrap/dist/js/bootstrap.bundle.min.js</span><span style="color: rgba(128, 0, 0, 1)">"</span>&gt;&lt;/script&gt;
&lt;script src=<span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">~/js/site.js</span><span style="color: rgba(128, 0, 0, 1)">"</span> asp-append-version=<span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">true</span><span style="color: rgba(128, 0, 0, 1)">"</span>&gt;&lt;/script&gt;<span style="color: rgba(0, 0, 0, 1)">
@await RenderSectionAsync(</span><span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">Scripts</span><span style="color: rgba(128, 0, 0, 1)">"</span>, required: <span style="color: rgba(0, 0, 255, 1)">false</span><span style="color: rgba(0, 0, 0, 1)">)

</body>

</html>

详细视图 [Action].cshtml

这个很常见，都认识，不介绍了，略过~。

运行效果

将下面这些数据，加到各自页面中，运行Index页面观察效果

<h2 style="color:red">_ViewStart.cshtml页面</h2>
<h2 style="color:green">_Layout.cshtml页面</h2>
<h2 style="color:darkgoldenrod">_ViewImport.cshtml页面</h2>
<h2 style="color:blue">Index.cshtml页面</h2>