GET and POST methods with the same Action name in the same Controller [duplicate]

Why is this incorrect?

{
    public class HomeController : Controller
    {

        [HttpGet]
        public ActionResult Index()
        {
            Some Code--Some Code---Some Code
            return View();
        }

        [HttpPost]
        public ActionResult Index()
        {
            Some Code--Some Code---Some Code
            return View();
        }

    }

How can I have a controlller thas answer one thing when is "getted" and one when is "posted"?

Since you cannot have two methods with the same name and signature you have to use the ActionName attribute:

[HttpGet]
public ActionResult Index()
{
  // your code
  return View();
}

[HttpPost]
[ActionName("Index")]
public ActionResult IndexPost()
{
  // your code
  return View();
}

Also see "How a Method Becomes An Action"

While ASP.NET MVC will allow you to have two actions with the same name, .NET won't allow you to have two methods with the same signature - i.e. the same name and parameters.

You will need to name the methods differently use the ActionName attribute to tell ASP.NET MVC that they're actually the same action.

That said, if you're talking about a GET and a POST, this problem will likely go away, as the POST action will take more parameters than the GET and therefore be distinguishable.

So, you need either:

[HttpGet]
public ActionResult ActionName() {...}

[HttpPost, ActionName("ActionName")]
public ActionResult ActionNamePost() {...}

Or,

[HttpGet]
public ActionResult ActionName() {...}

[HttpPost]
public ActionResult ActionName(string aParameter) {...}