mvc passing parameter to controller - asp.net-mvc-4

Question

I am very new to MVC
I need some help to over come the issue of passing parameter to a controller on form submit
what i have got is the following controller and the view
public ActionResult Index(string method ="None")
{
if (Request.HttpMethod == "POST")
{
switch (method)
{
case "Add10":
_bag.GetBag = Get100Products().Take(10).ToList<Product>();
break;
case "Clear":
_bag = null;
_bag.GetBag = null;
_bag = new Models.Bag();
break;
case "Add":
if ((Request.Form["Id"] != null) && (Request.Form["Id"] != ""))
{
if (_bag.GetBag.Count < 100)
{
var p = GetProduct(Request.Form["Id"]);
int qnt = Convert.ToInt16(Request.Form["qnt"]);
if (p.ItemNumber != null)
{
p.Quantity = qnt;
p.Index++;
_bag.Item = p;
}
}
}
break;
}
}
return View(_bag.GetBag);
}
and the view part of the view
<div style="vertical-align:middle">
#using (Html.BeginForm("", "Home", new { method = "Add10" }, FormMethod.Post))
{
<!-- form goes here -->
<input type="submit" value="Add 10 Items to bag" />
}
#using (Html.BeginForm("GetDiscount", "Home", FormMethod.Post))
{
<div>
<!-- form goes here -->
<input type="submit" value="Get Discount" />
With MAX time in seconds <input type="text" name="time" maxlength="2" value="2" />
</div>
}
#using (Html.BeginForm("", "Home", new { method = "Clear" }, FormMethod.Post))
{
<input type="submit" value="Empty the bag" />
}
</div>
so i am expecting when the use clicked button Add 10 Items to bag to pass the method value "Add10" to the index controller and when clicked Empty the bag to pass "Clear" the method value in index controller
but it always shows as "None"
what have I done wrong?
</form>

Answer 1

First of all, you have to add [HttpPost] to your controller in order to accept POST requests:
[HttpPost]
public ActionResult Index(string method ="None")
{

Answer 2

You should differentiate GET and POST actions.
You can do like this:
// [HttpGet] by default
public ActionResult Index(Bag bag = null)
{
// "bag" is by default null, it only has a value when called from IndexPOST action.
return View(bag);
}
[HttpPost]
public ActionResult Index(string method)
{
// Your logic as specified in your question
return Index(_bag.GetBag);
}
EDIT:
Your code is wrong, for example you will get a NullReferenceException because your try to call a property on a null object (_bag):
_bag = null;
_bag.GetBag = null; // NullReferenceException: _bag is null!
Also your code would be cleaner and more easier to maintain if we split this Action into several actions and follow the technology philosophy.
Do you consider refactoring this piece of code into smaller and more understandable chunks?