public override Task OnConnectedAsync() { HttpContext httpContext = Context.GetHttpContext(); string userIdB64 = httpContext.Request.Query["userId"].ToString(); string userId = ASCIIEncoding.ASCII.GetString(Convert.FromBase64String(userIdB64)); string connectionId = Context.ConnectionId; User user = _db.Users.Find(userId); UserConnectionId uci = _db.UserConnectionIds.Find(userId); if (uci == null) { uci = new UserConnectionId { User = user, ConnectionId = connectionId }; _db.UserConnectionIds.Add(uci); } else { uci.ConnectionId = connectionId; var k = _db.Update(dbObjectEntity: uci); } _db.SaveChanges(); return(base.OnConnectedAsync()); }