ASP.NET Core 3.1 MVC 应用程序 - 在子目录中搜索视图

Question

I know there is an area feature. But I think that is just to much for what I really need.

• I have an netcoreapp3.1 build from the MVC template
• I have a HomeController (namespace My.Project.Controllers )
• I also have a SettingsController (namespace My.Project.Controllers.Admin )
• In my _Layout.cshtml I link to the controller like this (generated link is https://localhost:5001/admin/settings/ as expected.

@if (User.IsInRole("admin"))
{
    <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle text-dark" href="#" id="navbarDropdown" role="button"
            data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
            Admin
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdown">
            <a class="dropdown-item" asp-area="" asp-controller="settings" asp-action="Index">Settings</a>
        </div>
    </li>
}

I also added the first MapControllerRoute to my Startup.Configure method

app.UseEndpoints(endpoints =>
{
    endpoints.MapControllerRoute(
            name: "admin",
            pattern: "admin/{controller=Home}/{action=Index}/{id?}"
            );
    endpoints.MapRazorPages();

    endpoints.MapControllerRoute(
        name: "default",
        pattern: "{controller=Home}/{action=Index}/{id?}");
    endpoints.MapRazorPages();
});

The controller is invoked and

public class SettingsController : Controller
{
    private readonly ISettingsProvider settingsProvider;

    public SettingsController(ISettingsProvider settingsProvider)
    {
        this.settingsProvider = settingsProvider;
    }

    public IActionResult Index()
    {
        var settings = settingsProvider.GetSettings();
        return View(settings);
    }
}

Now I get the following error

An unhandled exception occurred while processing the request. InvalidOperationException: The view 'Index' was not found. The following locations were searched:
/Views/Settings/Index.cshtml
/Views/Shared/Index.cshtml
/Pages/Shared/Index.cshtml

As I already said, I also tried using Areas but that would require me to put my files inside an Areas folder with its own Views folder and viewstart etc.

I worked a lot with nancy fx and I am used to the convention that views for My.Project.Modules.Admin.SettingsModule are searched inside Views/Admin/Settings first.

How do I achieve the same with ASP.NET Core MVC (for My.Project.Controllers.Admin.SettingsController search views in Views/Admin/Settings ?)

- src/
  - Views/
    - Home/
      - Index.cshtml
    - Admin/
       - Settings/
         - Index.cshtml
  - Controllers/
    - Admin/
        SettingsController.cs
    - HomeController.cs

Answer 1

Have you tried this?

@using (Html.BeginForm("Index", "Settings", "Admin" FormMethod.Get))
{
   @if (User.IsInRole("admin"))
   {
<li class="nav-item dropdown">
    <a class="nav-link dropdown-toggle text-dark" href="#" id="navbarDropdown" role="button"
        data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
        Admin
    </a>
    <div class="dropdown-menu" aria-labelledby="navbarDropdown">
        <a class="dropdown-item" asp-area="" asp-controller="settings" asp-action="Index">Settings</a>
    </div>
</li>

} }

Answer 2

I believe your issue is in the creation of the routing.

There is more information about this here

For your current configuration I think, if you change your pattern it will solve your issue

 pattern: "{area:exists}/{controller=Home}/{action=Index}/{id?}"

Answer 3

Solved

There are four things that I had to do.

First, I had to setup a new Controller Route inside Startup.Configure

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllerRoute(
                name: "areas",
                pattern: "{area:exists}/{controller=Home}/{action=Index}");

        endpoints.MapControllerRoute(
            name: "default",
            pattern: "{controller=Home}/{action=Index}/{id?}");

        endpoints.MapRazorPages();
    });

Second, I needed to tell my Controller that it belongs to the admin area.

[Area("admin")]
public class SettingsController : Controller
{
}

In my layout I had to set the asp-area property to admin

<a class="dropdown-item" asp-area="admin" asp-controller="settings" asp-action="Index">Settings</a>

but that was not enough since the default will only search in the following locations:

InvalidOperationException: The view 'Index' was not found. The following locations were searched:

/Areas/admin/Views/Settings/Index.cshtml
/Areas/admin/Views/Shared/Index.cshtml
/Views/Shared/Index.cshtml
/Pages/Shared/Index.cshtml

So I had to add this to the ConfigureServices method.

services.Configure<RazorViewEngineOptions>(options =>
    {
        // {0} - Action Name
        // {1} - Controller Name
        // {2} - Area Name
        options.AreaViewLocationFormats.Add("/Views/{2}/{1}/{0}.cshtml");
    });