Prime number utilities

primalityTest.cs

public static bool IsPrime(int candidate) {
    if ((candidate & 1) == 0)
        return candidate == 2;
    for (int i = 3; (i * i) <= candidate; i += 2)
        if ((candidate % i) == 0)
            return false;
    return candidate != 1;
}

primeList.cs

public static IEnumerable<int> ComputePrimes(int limit)
{
    limit++;
    var primes = new BitArray(limit, true);
    primes.Set(0, false);
    primes.Set(1, false);
    var lastI = 0;
    for (int i = 0; i * i < limit; i++)
    {
        if (primes.Get(i))
        {
            yield return i;
            for (int j = i * i; j < limit; j += i)
            {
                primes.Set(j, false);
            }
        }
        lastI = i;
    }
    for(var i = lastI + 1; i < limit; i++){
        if(primes.Get(i)) yield return i;
    }
}