[c#] MVC : The parameters dictionary contains a null entry for parameter 'k' of non-nullable type 'System.Int32'

I am new to MVC. In My Application , I'm Retrieving the Data from Mydatabase. but when I run my Application it show Error Like This this is my url

http://localhost:7317/Employee/DetailsData/4



  Exception Details: System.ArgumentException: The parameters dictionary contains a null entry for parameter 'k' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult DetailsData(Int32)' in 'MVCViewDemo.Controllers.EmployeeController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Parameter name: parameters

this is my web.config file code

<connectionStrings>
  <add name="EmployeeContext" connectionString="Server=.;Database=mytry;integrated security=true; ProviderName=System.Data.SqlClient"/>
</connectionStrings>

this is my Employee Model Class(Employee.cs)

[Table("emp")]    /* to map tablename with our class name*/
    public class Employee
    {
        public int EmpId { get; set; }
        public string Name { get; set; }
        public string Gender { get; set; }
        public string City { get; set; }

    }

My EmployeeContext.cs Model class

 public class EmployeeContext:DbContext
    {
        public DbSet<Employee> Employees { get; set; }
    }

my EmployeeController.cs

 public ActionResult DetailsData(int k)
        {

            EmployeeContext Ec = new EmployeeContext();
            Employee emp = Ec.Employees.Single(X => X.EmpId == k);           
            return View(emp);
        }

and my view

<h2>DetailsData</h2>
@Model.Name<br />
@Model.City<br />
@Model.Gender<br />
@Model.EmpId

It seems that your action needs k but ModelBinder can not find it (from form, or request or view data or ..) Change your action to this:

public ActionResult DetailsData(int? k)
    {

        EmployeeContext Ec = new EmployeeContext();
        if (k != null)
        {
           Employee emp = Ec.Employees.Single(X => X.EmpId == k.Value);

           return View(emp);
        }
        return View();
    }

Also make sure the value is not too large or too small for int like in my case.

I am also new to MVC and I received the same error and found that it is not passing proper routeValues in the Index view or whatever view is present to view the all data.

It was as below

<td>
            @Html.ActionLink("Edit", "Edit", new { /* id=item.PrimaryKey */ }) |
            @Html.ActionLink("Details", "Details", new { /* id=item.PrimaryKey */ }) |
            @Html.ActionLink("Delete", "Delete", new { /* id=item.PrimaryKey */ })
        </td>

I changed it to the as show below and started to work properly.

<td>
            @Html.ActionLink("Edit", "Edit", new { EmployeeID=item.EmployeeID }) |
            @Html.ActionLink("Details", "Details", new { /* id=item.PrimaryKey */ }) |
            @Html.ActionLink("Delete", "Delete", new { /* id=item.PrimaryKey */ })
        </td>

Basically this error can also come because of improper navigation also.

I faced this error becouse I sent the Query string with wrong format

http://localhost:56110/user/updateuserinfo?Id=55?Name=Basheer&Phone=(111)%20111-1111
------------------------------------------^----(^)-----------^---...
--------------------------------------------must be &

so make sure your Query String or passed parameter in the right format