AmazonScrape.PageManager.PageManager C# (CSharp) Method

        public PageManager(int pageNumber,
            SearchCriteria criteria,
            Func<int, string, string> pageLoadMethod, // see explanation above
            ProgressChangedEventHandler updateProgressMethod,
            RunWorkerCompletedEventHandler workerCompleteMethod)
        {
            if (pageNumber < 1)
            {
                string msg = "Supplied page number ({0}) was < 0!";
                msg = string.Format(msg,pageNumber);
                throw new ArgumentOutOfRangeException(msg);
            }

            if (pageLoadMethod == null)
            {
                string msg = "Provided a null method to obtain page HTML!";
                throw new InvalidOperationException(msg);
            }

            ProgressChanged += updateProgressMethod; // Callback
            RunWorkerCompleted += workerCompleteMethod;  // Callback
            DoWork += Work;

            _pageLoadMethod = pageLoadMethod;
            _searchCriteria = criteria;
            _pageNumber = pageNumber;

            WorkerReportsProgress = true;
            WorkerSupportsCancellation = true;
        }