GET and POST methods with the same Action name in the same Controller

I like to accept a form post for my POST actions, even if I don't need it. For me it just feels like the right thing to do as you're supposedly posting something.

public class HomeController : Controller
{
    public ActionResult Index()
    {
        //Code...
        return View();
    }

    [HttpPost]
    public ActionResult Index(FormCollection form)
    {
        //Code...
        return View();
    }
}

To answer your specific question, you cannot have two methods with the same name and the same arguments in a single class; using the HttpGet and HttpPost attributes doesn't distinguish the methods.

To address this, I'd typically include the view model for the form you're posting:

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

    [HttpPost]
    public ActionResult Index(formViewModel model)
    {
        do work on model --
        return View();
    }

}

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) {...}

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"