add Oauth link

Hi,

In my code I'm trying to create a new user, and I also want to add a new Oauth link, because our users connect to the community

using Oauth. I'm at the point in which I created the user and I want to add the new OAuthLink, but it needs a clientTypeclientUserId and a userId.

    public class OAuthLink
    {
        public OAuthLink(string clientType, string clientUserId, int userId);

        public string ClientType { get; set; }
        public string ClientUserId { get; set; }
        public int UserId { get; set; }
    }

I have the clientType and the userId, but how do I get a new clientUserId so it won't generate a duplicate in the community, or better yet how are clientUserId's generated?

            //the code I'm trying to use
            OAuthLink newLink = new OAuthLink(ClientType, userID, clientUserID);
            _OAuthService.AddOAuthLink(newLink);

Regards,

Silviu