No, using the same instance from multiple threads can cause it to break and return all 0’s. However, creating a thread-safe version (without needing nasty locks on every call to Next()) is simple. Adapted from the idea in this article:
public class ThreadSafeRandom
{
private static readonly Random _global = new Random();
[ThreadStatic] private static Random _local;
public int Next()
{
if (_local == null)
{
int seed;
lock (_global)
{
seed = _global.Next();
}
_local = new Random(seed);
}
return _local.Next();
}
}
The idea is to keep a separate static Random variable for each thread. Doing that in the obvious way fails, however, because of another issue with Random – if multiple instances are created at nearly the same time (within about 15ms), they will all return the same values! To fix this, we create a globally-static Random instance to generate the seeds used by each thread.
The above article, by the way, has code demonstrating both of these issues with Random.