Attribute routing is not working properly in asp.net core 3.0 - asp.net-core

Question

I was trying to migrate my application from asp.net core 2.1 to 3.0 which uses attribute routing
My Startup file's ConfigureServices and Configure methods:
public void ConfigureServices(IServiceCollection services)
{
services.ConfigureOptions(typeof(ABCClass));
services.AddTransient<ITagHelperComponent, XYZTagHelperComponent>();
services.AddMvc();
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseStaticFiles();
app.UseMvcWithDefaultRoute();
}
I have replaced services.AddMvc(); with services.AddMvc(options => options.EnableEndpointRouting = false); to disable Endpoint routing
My action method:
[Route("")]
[Route("Machines")]
public async Task<ViewResult> GetMachinesAsync()
{
return View("MachineView");
}
First time my application loads with MachineView, but when I try to call same action method on it gives me 404 error (page can’t be found)
action call from .cshtml file:
<li class="nav-item">
<a class="nav-link"
href="#Url.Action("GetMachinesAsync", "Machine")">
Machines
</a>
</li>
Can you please help me out if I am missing something here, or I have done something wrong while configuring middleware for routing.
Thanks in Advance.

Answer 1

Async suffix for controller action names will be trimmed by default in asp.net core 3.0.
Refer to https://stackoverflow.com/a/59024733/10158551
Solution1:
Replace GetMachinesAsync to GetMachines in view.
<li class="nav-item">
<a class="nav-link"
href="#Url.Action("GetMachines", "Machine")">
Machines
</a>
</li>
Solution2:
Keep using GetMachinesAsync
<li class="nav-item">
<a class="nav-link"
href="#Url.Action("GetMachinesAsync", "Machine")">
Machines
</a>
</li>
then disable that behavior in startup
services.AddMvc(options =>
{
options.EnableEndpointRouting = false;
options.SuppressAsyncSuffixInActionNames = false;
});

Answer 2

You don't require async suffixes for action methods. So if you want to refer GetMachinesAsync you need to use GetMachines, like this.
<li class="nav-item">
<a class="nav-link"
href="#Url.Action("GetMachines", "Machine")">
Machines
</a>
</li>