ASP.NET #C System.IndexOutOfRangeException:

[TheSyntaX]

Hey, I am pretty new to ASP.NET, trying to run basic query to get latest entry ID from table (since this shit doesn't have auto increment [I didn't find any way to make it])
but when I run the code it just gives me error.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.SqlClient;
using System.Configuration;
using System.Data.Sql;


namespace AITProjectX11413088
{
    public class SQLHelpers
    {
        public int GetLatestID(String type)
        {
            String query = "SELECT Max(ides) FROM "+type;
            String connStr = ConfigurationManager.ConnectionStrings["RevsConnectionString"].ConnectionString;
            SqlConnection sqli = new SqlConnection(connStr);
            sqli.Open();
            SqlCommand cmd = new SqlCommand(query, sqli);
            SqlDataReader dr = cmd.ExecuteReader();
            String num = dr["ides"]+1.ToString();
            return Int32.Parse(num);
        }


    }
}

Any help?
Stuck with this for quite a while now.

Thanks.

[Nisd]

Having changing table names is a bad idea.

Anyways, try using "[URL="http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.executescalar(v=vs.110).aspx"]ExecuteScalar[/URL]" instead of creating a DataReader.

[TheSyntaX]

[QUOTE=Nisd;43203997]Having changing table names is a bad idea.

Anyways, try using "[URL="http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.executescalar(v=vs.110).aspx"]ExecuteScalar[/URL]" instead of creating a DataReader.[/QUOTE]
Well I just don't want to create different functions if one can do the thing?

[editline]16th December 2013[/editline]

public int GetLatestID(String type)
        {
            String query = "SELECT MAX(Id) FROM "+type;
            String connStr = ConfigurationManager.ConnectionStrings["RevsConnectionString"].ConnectionString;
            SqlConnection sqli = new SqlConnection(connStr);
            sqli.Open();
            SqlCommand cmd = new SqlCommand(query, sqli);
            String dr = cmd.ExecuteScalar().ToString();
            var firstColumn = cmd.ExecuteScalar();
            int id = 0;
            if (firstColumn != null)
            {
                id = Convert.ToInt32(firstColumn.ToString());
            }
            return id;
        }

Now it gives me:Input string was not in a correct format.

[editline]16th December 2013[/editline]

Derp... I am an idiot, I missed and didn't add value to one of the fields...

[Nisd]

Should remove

[QUOTE]
String dr = cmd.ExecuteScalar().ToString();
[/QUOTE]