Edit link passing null value when click on that link

Question

Hi,

In my view code I have written code for editing a record

 

<td> @Html.ActionLink("Edit", "Edit","PO", new { id = item.Sl_No }) |

@Html.ActionLink("Details", "Details", new { id = item.Tracking }) </td>

<td>@item.Tracking</td>

<td>@item.Project_No</td>

<td>@item.Project_Phase</td>

<td>@item.Project_No_Description</td>

<td>@item.Requester</td>

<td>@item.Date_Requested</td>

 

When loading the data I am able to see the fields mentioned in the script,

But In controller code

 

public ActionResult Edit(int SlNo)

{

var viewModel = new POViewModel();

viewModel.Order = PODb.orders.Single(x => x.Sl_No == SlNo);

viewModel.Order = (order)PODb.orders.Where(x => x.Sl_No == SlNo);

return View(viewModel);

}

 

Here In the above code I am getting the parameter value as null as it is throwing the below exception

"

The parameters dictionary contains a null entry for parameter 'SlNo' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult Edit(Int32)' in 'PurchaseOrder.Controllers.POController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Parameter name: parameters" 

 Could any one please help me how to rectify this one?