Error 404 when pressing button

[chairmanPC]

This is my first ASP.NET Core project. I started with adding a button that will check if it is clicked. It will print a YES when it's clicked. but when I hit the button, I got into this Error 404 page. What did I do wrongly?

@{
    ViewData["Title"] = "Index";
}

<form class="text-center">
    <button name="button" asp-action="checkValue">Check if Pressed</button>
</form>
<div class="text-center">
    Status: @TempData["status"]
</div>

And this below is my btnCheckController.

namespace firstASPNETApp.Controllers
{
    public class btnCheckController : Controller
    {
        public IActionResult Index()
        {
            return View();
        }

        public IActionResult checkValue()
        {
            TempData["status"] = "YES";
            return RedirectToAction("Index");
        }
    }
}

}

Where did I do wrongly?

 

[Skydiver]

What was the URL on the browser before clicked on the button?
What was the URL on the browser when you got the 404 error?

 

[chairmanPC]

What was the URL on the browser before clicked on the button?
What was the URL on the browser when you got the 404 error?

I fixed it. I realized wrote the method in the buttonController file, rather than the homeController file where I should have written it. My index page is my default starting page, so when I clicked the button, the error yelled at me that it cannot find the method, because I did not write it in the homeController file. As soon as I moved the block of code into the homeController file, the web page was able to find the function, and it displayed correctly.