How to generate 8 bytes unique id from GUID?

Question

I try to use long as unique id within our C# application (not global, and only for one session) for our events. Do you know if the following will generate an unique long id?

Answer 1

Like a few others have said, only taking part of the guid is a good way to ruin its uniqueness. Try something like this:

var bytes = new byte[8];
using (var rng = new RNGCryptoServiceProvider())
{
    rng.GetBytes(bytes);
}

Console.WriteLine(BitConverter.ToInt64(bytes, 0));