ASP.NET Core MVC no webpage was found for web address

Question

I am currently learning .NET Core and I'm trying to make a user management using Identity framework in ASP.NET Core MVC 3.1. In the Controllers I have a RoleManagerController with EditRole GET and POST like this:

    [HttpGet]
    public async Task<IActionResult> EditRole(string roleId)
    {
        ViewBag.roleId = roleId;

        var role = await _roleManager.FindByIdAsync(roleId);

        if (role == null)
        {
            ViewBag.ErrorMessage = $"Role with RoleID = {roleId} doest not exists.";
            return NotFound();
        }

        // create new roleModel 
        var roleModel = new EditRoleViewModel
        {
            RoleId = role.Id,
            RoleName = role.Name
        };

        // retrieve all users based on current role 
        foreach (var user in _userManager.Users.ToList())
        {
            if (await _userManager.IsInRoleAsync(user, role.Name))
            {
                roleModel.Users.Add(user.UserName);
            }
        }

        return View(roleModel);
    }

    [HttpPost]
    public async Task<IActionResult> EditRole(EditRoleViewModel roleModel)
    {
        var role = await _roleManager.FindByIdAsync(roleModel.RoleId);

        if (role == null)
        {
            ViewBag.ErrorMessage = $"Role with RoleId = {roleModel.RoleId} does not exists.";
            return NotFound();
        }
        else
        {
            role.Name = roleModel.RoleName;
            // update the role 
            var updateStatus = await _roleManager.UpdateAsync(role);

            // check while updating is succeed or not 
            if (updateStatus.Succeeded)
            {
                return RedirectToAction("Index");
            }

            foreach (var error in updateStatus.Errors)
            {
                ModelState.AddModelError("updating failed", error.Description);
            }   
        }

        return View(roleModel);
    }

Based on EditRole GET, I created a view named EditRole.cshtml in Views/RoleManager folder, like this:

@model EditRoleViewModel
@{ 
    ViewData["Title"] = "Edit Role";
} 

<h4>Edit Role</h4><br />

<form class="" method="post">
    <div asp-validation-summary="All" class="text-danger"></div>
    <div class="form-group">
        <label asp-for="RoleId" class="col-sm-2 col-form-label"></label>
        <div class="col-sm-10">
            <input asp-for="RoleId" class="form-control" disabled/>
        </div>
    </div>
    <div class="form-group">
        <label asp-for="RoleName" class="col-sm-2 col-form-label"></label>
        <div class="col-sm-10">
            <input asp-for="RoleName" class="form-control"/>
            <span asp-validation-for="RoleName" class="text-danger"></span>
        </div>
    </div>
    <div class="form-group">
        <div class="col-sm-10">
            <button type="submit" class="btn btn-primary">Update</button>
            <a asp-action="Index" class="btn btn-secondary">Cancel</a>
        </div>
    </div>
</form>

This is something that I configured in Startup.cs

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

But when I try to edit role and access the route with role's id the page said no webpage was found for the web address.. Am I missing something?

Answer 1

Just for a moment I decided to check all the script those are related to the problem route and I realized that the tag helper I provided in Edit button in the Index.cshtml which link to the route was set to asp-route-id=@role.Id which will not work, then I try to change it to asp-route-roleId=@role.Id , the roleId is what I defined in the RoleManagerViewModel. Now it worked well.

Answer 2

The problem may be that you do not specify Area !

if you put this section into Separate Area you must Definition one new route at startup.cs same this :

routes.MapRoute(
                name: "areas",
                template: "{area:exists}/{controller=Home}/{action=Index}/{id?}"
                );