Asp.Net Core 端点路由

Question

I have an Action in a Controller :

[Route("")]
[Route("{pageNumber?}")]
[Route("tag/{tagSlug?}/{pageNumber?}")]
public async Task<IActionResult> Index(int? pageNumber, string tagSlug = null, string searchTerm = null)
{
    var model = await repoPm_.GetPage(pageNumber, tagSlug, searchTerm);
    return View(model);
}

Each item has a list of tags associated with it

@foreach (var t in item.Tags)
{
    <a asp-action="Index" asp-route-tagSlug="@t.TagSlug" class="mr-3">@t.Name</a>
}

And in my navbar i have a link to the page, which, I've tried the following:

<a asp-area="" asp-controller="Items" asp-action="Index" asp-route-tagSlug="">Items</a>
<a asp-area="" asp-controller="Items" asp-action="Index" asp-route-tagSlug="@null">Items</a>
<a asp-area="" asp-controller="Items" asp-action="Index">Items</a>

When I'm not on that page, the link in the navbar points to /items/tag which is annoying, but it works.

When I am on that page and I've clicked on one of the tags then the Url in the Omnibar is proper, ie /items/tag/fancy-items

The problem is that is also the generated url for the link in my navbar, ie /items/tag/fancy-items when it should be just /items

What am i doing wrong? I don't want to get into a bunch of route-mapping in Startup.cs , seems like <a asp-area="" asp-controller="Items" asp-action="Index">Items</a> should just work

Answer 1

You can use overloads to separate your different routes such that their URLs are discrete from one another.

This way, calling your Index action with no parameters can only ever be reached by /items , and the run-time binding behavior of ASP.NET will not incorrectly resolve to a different URL.

My suggestion would be to make the top-level Action calls overloads that resolve to the same underlying method for reusability.

[Route("")]
public async Task<IActionResult> Index()
{
    return await WrappedMethod(null);
}


[Route("tag/{pageNumber}")]
public async Task<IActionResult> Index(int pageNumber)
{
    return await WrappedMethod(pageNumber);
}

[Route("tag/{tagSlug}/{pageNumber}")]
public async Task<IActionResult> Index(string tagSlug, int? pageNumber)
{
    return await WrappedMethod(pageNumber, tagSlug);
}

private async Task<IActionResult> WrappedMethod(int? pageNumber, string tagSlug = null, string searchTerm = null)
{
    var model = await repoPm_.GetPage(pageNumber, tagSlug, searchTerm);
    return View(model);
}

Note that the nullability of the parameters themselves will depend on your use-cases.