C#: Calculating prime numbers using the Standard (Naive) Method

gistfile1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace StandardMethod
{

    class Program
    {
        static void Main(string[] args)
        {
            DateTime dtStart = DateTime.Now;
            GeneratePrimesNaive( 1000000 );
            Console.WriteLine( DateTime.Now - dtStart );
            Console.Read();
        }

        public static List<int> GeneratePrimesNaive(int n)
        {
            List<int> primes = new List<int>();
            primes.Add( 2 );
            int nextPrime = 3;
            while ( primes.Count < n )
            {
                int sqrt = (int)Math.Sqrt( nextPrime );
                bool isPrime = true;
                for ( int i = 0 ; (int)primes[i] <= sqrt ; i++ )
                {
                    if ( nextPrime % primes[i] == 0 )
                    {
                        isPrime = false;
                        break;
                    }
                }
                if ( isPrime )
                {
                    primes.Add( nextPrime );
                }
                nextPrime += 2;
            }
            return primes;
        }


    }
}