ASP.NET Web API - SQL - Retrieving Information - sql

Question

I am having some issues with retrieving information from sql database using ASP.net Web API.
I have tried to use forms, which worked great (using gridview) but when I try to do it using a separate class dedicated to store my specific table information I get this error:
"Index was out of range. Must be non-negative and less than the size of the collection."
This is the code:
public ActionResult Details()
{
List<Employee> employeeList = new List<Employee>();
string CS = ConfigurationManager.ConnectionStrings["EmployeeContext"].ConnectionString;
using (var myConn = new SqlConnection(CS))
{
SqlCommand cmd = new SqlCommand("select * from tblEmployee", myConn);
myConn.Open();
SqlDataReader rdr = cmd.ExecuteReader();
while (rdr.Read())
{
int i = 0;
employeeList[i].PersonID = Convert.ToInt32(rdr["PersonID"]);
employeeList[i].Name = rdr["Name"].ToString();
employeeList[i].Gender = rdr["Gender"].ToString();
employeeList[i].City = rdr["City"].ToString();
employeeList[i].DepartmentID = Convert.ToInt32(rdr["DepartmentID"]);
i++;
}
return View(employeeList);
}
}
This is the Employee class:
[Table("tblEmployee")]
public class Employee
{
public int PersonID { get; set; }
public string Name { get; set; }
public string Gender { get; set; }
public string City { get; set; }
public int DepartmentID { get; set; }
}
}
I get this error on any of the retrieving information lines.
The table has 5 columns: PersonID(int PK), Name(nvarchar), Gender(nvarchar), City(nvarchar), DepartmentID(int).
I checked many times the columns names to make sure I didn't got those wrong and I double checked the connection string which is also fine (the same code works with gridview using forms API).
Hope someone can help me with this. I didn't find any specific information on that and I guess it's should be easy and I'm doing something wrong here.

Answer 1

You are trying to populate a List<> object by using an index. To populate a List<> you need to use .Add(). You need to change your code from this:
int i = 0;
employeeList[i].PersonID = Convert.ToInt32(rdr["PersonID"]);
employeeList[i].Name = rdr["Name"].ToString();
employeeList[i].Gender = rdr["Gender"].ToString();
employeeList[i].City = rdr["City"].ToString();
employeeList[i].DepartmentID = Convert.ToInt32(rdr["DepartmentID"]);
i++;
To this:
Employee emp = new Employee();
emp.PersonID = Convert.ToInt32(rdr["PersonID"]);
emp.Name = rdr["Name"].ToString();
emp.Gender = rdr["Gender"].ToString();
emp.City = rdr["City"].ToString();
emp.DepartmentID = Convert.ToInt32(rdr["DepartmentID"]);
employeeList.Add(emp);

Answer 2

When adding a new item to a list, you should use .Add(). Here's one option:
while (rdr.Read())
{
employeeList.Add(new Employee {
PersonID = Convert.ToInt32(rdr["PersonID"]),
Name = rdr["Name"].ToString(),
Gender = rdr["Gender"].ToString(),
City = rdr["City"].ToString(),
DepartmentID = Convert.ToInt32(rdr["DepartmentID"])
});
}
You could then access individual items in the list with their index or by using foreach.