Amit Kumar Amit Kumar - 3 months ago 30
C# Question

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

Answer

It appears that you are using the default route which is defined as this:

routes.MapRoute(
    name: "Default",
    url: "{controller}/{action}/{id}",
    defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
);

The key part of that route is the {id} piece. If you look at your action method, your parameter is k instead of id. You need to change your action method to this so that it matches the route parameter:

// change int k to int id
public ActionResult DetailsData(int id)

If you wanted to leave your parameter as k, then you would change the URL to be:

http://localhost:7317/Employee/DetailsData?k=4

You also appear to have a problem with your connection string. In your web.config, you need to change your connection string to this (provided by haim770 in another answer that he deleted):

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