Multiple actions matched

Question

I have migrated to ASP.NET Core 2.1.I'd like to submit a form (Insert method from ArticleController: url: http://localhost:52125/article/insert) but I got this error:

An unhandled exception occurred while processing the request. AmbiguousActionException: Multiple actions matched. The following actions matched route data and had all constraints satisfied:

Jahan.Beta.Web.App.Controllers.ArticleController.Insert (Jahan.Beta.Web.App) Jahan.Beta.Web.App.Controllers.ArticleController.Edit (Jahan.Beta.Web.App) Jahan.Beta.Web.App.Controllers.ArticleController.DeleteConfirmed (Jahan.Beta.Web.App) Microsoft.AspNetCore.Mvc.Internal.ActionSelector.SelectBestCandidate(RouteContext context, IReadOnlyList candidates)

How can I solve it? and is there a way to improve/optimize routes.MapRoute?

Article Controller:

[Route("[controller]")]
public class ArticleController : Controller
{
   [HttpPost]
   public async Task<IActionResult> Insert([FromBody]Article article)
   {
      // I want to run this method!
   }

   [HttpGet("Edit/{id}")]
   public async Task<IActionResult> Edit(int? id)
   {
   }
   [HttpPost]
   [ValidateAntiForgeryToken]
   public async Task<IActionResult> Edit(int id, [FromBody] Article article)
   {
   }

   [HttpPost, ActionName("DeleteConfirmed/{id}")]
   public async Task<IActionResult> DeleteConfirmed(int id)
   {
   }
}

a part of startup.cs file:

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        app.UseDeveloperExceptionPage();
        app.UseStatusCodePages();
        app.UseStaticFiles();
        app.UseAuthentication();

        var provider = new FileExtensionContentTypeProvider();
        provider.Mappings[".less"] = "plain/text";

        app.UseStaticFiles(new StaticFileOptions
        {
            ContentTypeProvider = provider
        });

        ApplicationDbContext.CreateAdminAccount(app.ApplicationServices, Configuration).Wait();

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

            routes.MapRoute(
                name: "AdminAreasUsers",
                template: "{area:exists}/{controller=Users}/{action=Index}/{id?}"
            );
            routes.MapRoute(
                name: "AdminAreasDeleteUser",
                template: "{area:exists}/{controller=Users}/{action=Delete}/{id}"
            );
            routes.MapRoute(
               name: "FilterByTagAsync",
               template: "{controller}/{action}/{tagId}/{articlePage}",
               defaults: new { controller = "Article", action = "FilterByTagAsync", tagId = "", articlePage = "" }
           );
            routes.MapRoute(
               name: "ShowArticle",
               template: "{controller}/{action}/{Id}",
               defaults: new { controller = "Article", action = "Show", Id = "" }
           );

            routes.MapRoute(
               name: "default",
               template: "{controller}/{action}",
               defaults: new { controller = "Home", action = "Index" }
           );
            routes.MapRoute(
                name: "About",
                template: "{Controller=AboutUs}/{action=AboutUs}/{id?}");

        });

        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            app.UseHsts();
        }
    }

Answer 1

You're using attribute-based routing, but haven't applied any routes to any of those actions. As such, they're all using the default of "", or an empty route. You need to do something like:

[HttpPost("insert")]
public async Task<IActionResult> Insert([FromBody]Article article)

[HttpGet("Edit/{id}")]
public async Task<IActionResult> Edit(int? id)

[HttpPost("edit/{id}")]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Edit(int id, [FromBody] Article article)

[HttpPost("delete"), ActionName("DeleteConfirmed/{id}")]
public async Task<IActionResult> DeleteConfirmed(int id)