Convert .NET Guid to MongoDB ObjectID

Question

How can I convert a .NET GUID to a MongoDB ObjectID (in C#). Also, can I convert it back again to the same GUID from the ObjectID?

Answer 1

FYI You can convert from an ObjectId to a Guid

    public static Guid AsGuid(this ObjectId oid)
    {
        var bytes = oid.ToByteArray().Concat(new byte[] { 5, 5, 5, 5 }).ToArray();
        Guid gid = new Guid(bytes);
        return gid;
    }

    /// 

    /// Only Use to convert a Guid that was once an ObjectId
    /// 
    public static ObjectId AsObjectId(this Guid gid)
    {
        var bytes = gid.ToByteArray().Take(12).ToArray();
        var oid = new ObjectId(bytes);
        return oid;
    }