Asp.net MVC3, C#, Figure out Single or Multiple Json paramter?

Question

I'm passing to single JSON type parameter and multiple JSON type parameters to Asp.Net.

and in Asp.Net, I need to figure out the parameter is single data or multiple data to update DB (EF, Repository pattern).

[Single]

[Multiple]

Firstly, I tried like this,

[HttpPost]
public ActionResult ItemUpdate(WEBORDERLN ln ,IList<WEBORDERLN> lns)
{

but it comes to ln always. it never go to lns :(

[HttpPost]
public ActionResult ItemUpdate(WEBORDERLN ln)
{
// it works for only single update

and

[HttpPost]
public ActionResult ItemUpdate(IList<WEBORDERLN> lns)
{
// it works for only multiple update

How I figure out, the JSON type parameter is single or multiple?

anybody know, please advice me.

Thank you!

[EDIT]

[HttpPost]
public ActionResult ItemUpdate(WEBORDERLNS lns)
{
    try
    {
    EFWebOrderLnRepository webOrderLn = new EFWebOrderLnRepository();

    log.Debug("Count : "+lns.lns.Count.ToString()); // Object reference not set to an instance of an object.    
    log.Debug(lns.lns.Count());  //null, error : Value cannot be null
    log.Debug(lns.lns.Count().ToString());  //null, error : Value cannot be null

    foreach (WEBORDERLN ln in lns.lns)
    {
        webOrderLn.updateWebOrderLn(ln); // Error : Object reference not set to an instance of an object
    }
    .
    .
    .


public class WEBORDERLNS
{
    public IList<WEBORDERLN> lns { get; set; }
}

[EDIT]

Accept  text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding gzip, deflate
Accept-Language en-us,en;q=0.5
Connection  keep-alive
Content-Length  875
Content-Type    application/json; charset=UTF-8
Cookie  user=38C6C07684B04645821CA5273EAB5B34340CE8CCA13A7D67DC748819B02C6963E4AD2A322068FC3090D3FE03EC81E663A5DED6FF2534E2595B40CF57EFF9BB544FFAC95CD79020E8A94019A3DC53B769EFC4049B6B9627E98AD9DBC1431BB5D99A47625B3353FA697A1CC005855C0248E95F61F7BD4A5362D75E5D01B395FB14E078524B8D0C7219AF959F9AED188AB30A16187DE166D5BD008B0013A65D470C52C9408C47FD42672B8FBABDB3524F77
Host    localhost:49995
Referer http://localhost:49995/
User-Agent  Mozilla/5.0 (Windows NT 6.1; WOW64; rv:14.0) Gecko/20100101 Firefox/14.0.1
X-Requested-With    XMLHttpRequest

[EDIT]

Answer 1

You would actually be far better off creating a Model class which represents an order set, with a collection of WEBORDERLN exposed as a property.

public class OrderSet 
{
   public List<WEBORDERLN> OrderLines { get; set; }

}

On your controller method, change the incoming parameter to:-

[HttpPost]
public ActionResult ItemUpdate(OrderSet orders)
{
// it works for only multiple update

At that point, when receiving the model, you can just call the count mechanism on your OrderLines property.

// How many orders?
var orderCount = orders.OrderLines.Count;