Correct way to use Random in multithread application [duplicate]

Answer 1

readonly ThreadLocal random = 
    new ThreadLocal(() => new Random(GetSeed()));

int Rand()
{
    return random.Value.Next();
}

static int GetSeed()
{
    return Environment.TickCount * Thread.CurrentThread.ManagedThreadId;
}

(shamelessly stolen from the comment of Jeroen Vannevel)