[DllImport("rpcrt4.dll", SetLastError = true)] static extern int UuidCreateSequential(out Guid guid); public static Guid GenGuid() { const int RPC_S_OK = 0; Guid guid; int result = UuidCreateSequential(out guid); if (result != RPC_S_OK) { throw new ApplicationException("Create sequential guid failed: " + result); } return guid; }