Question

I have a multiple values in ListBox. When I am Selecting a Single Value my code is working fine.

But when I am Selecting Multiple Values it is giving me this Exception:-

Index was outside the bounds of the array.

My code is:

if (submitButton == "Enroll Trainee")
{
    if (Request.Form["NonEnroll"] != null)
    {
        int i = 0;
        string[] selected = Request.Form["NonEnroll"].Split(',');
        if (selected != null)
        {
            if (selected.Count() != 0)
            {
                foreach (var item in selected)
                {
                    enrollDetails.TraineeID = Convert.ToInt32(item[i].ToString());//Getting Exception here
                    enrollDetails.TrainerID = Convert.ToInt32(Session["user"].ToString());
                    enrollDetails.dt = DateTime.Now;
                    db.EnrollTrainee.Add(enrollDetails);
                    db.SaveChanges();
                    i++;
                }

            }
        }
        populatelistbox();
        return View();
    }
}

During the First Iteration it is working fine and also save first iteration result in my database. But when it starts second iteration it give me the above exception

Answer 1

You misused the loop variable, I guess you need:

enrollDetails.TraineeID = Convert.ToInt32(item);

Let me explain why you original code item[i].ToString() didn’t worked:

Lets assume you got the list "2,1,3" then with the string split you have created the array of strings : new [] { "2", "1", "3" }

Then in your loop

1. In the first iteration

   • item was "2"
   • i was 0

   So item[i] resolved in "2"[0] which is "2" and it worked.

2. In the second iteration

   • item was "1"
   • i was 1

   and your code resolved in "1"[1] which thrown an exception because "1" is only one character long so the Index was outside the bounds of the array.