How can I safely loop until there is nothing more to do without using a “placeholder” while conditon?

Question

In order to call my Web API method until no more data is returned (I\'m fetching it in batches, to keep each result set small, due to the 98-lb-weakling persona of the client (W

Answer 1

Consider using a do..while() loop. This gets you around the "while-loop-is-never-reached" problem... it will always run at least once, no matter what moreRecordsExist is set to.

do
{
    redemptionsList.redemptions.Clear();
    string uri = String.Format("http://platypus:28642/api/Redemptions/{0}/{1}",     lastIdFetched, RECORDS_TO_FETCH);
    var webRequest = (HttpWebRequest)WebRequest.Create(uri);
    webRequest.Method = "GET";

    using (var webResponse = (HttpWebResponse)webRequest.GetResponse())
    {
        if (webResponse.StatusCode == HttpStatusCode.OK)
        {
            var reader = new StreamReader(webResponse.GetResponseStream());
            string s = reader.ReadToEnd();
            var arr = JsonConvert.DeserializeObject(s);
            if (arr == null) break;

            foreach (JObject obj in arr)
            {
                id = obj.Value("Id") ?? 0;
                var _redemptionId = obj.Value("RedemptionId") ?? "";
                var _redemptionItemId = obj.Value("RedemptionItemId") ?? "";
                var _redemptionName = obj.Value("RedemptionName") ?? "";
                double _redemptionAmount = obj.Value("RedemptionAmount") ?? 0.0;    
                var _redemptionDept = obj.Value("RedemptionDept") ?? "";
                var _redemptionSubdept = obj.Value("RedemptionSubDept") ?? "";

                redemptionsList.redemptions.Add(new HHSUtils.Redemption
                {
                    Id = id,
                    RedemptionId = _redemptionId,
                    RedemptionItemId = _redemptionItemId,
                    RedemptionName = _redemptionName,
                    RedemptionAmount = _redemptionAmount,
                    RedemptionDept = _redemptionDept,
                    RedemptionSubDept = _redemptionSubdept,
                });
            } // foreach
        } // if ((webResponse.StatusCode == HttpStatusCode.OK) && (webResponse.ContentLength > 2))
    } // using HttpWebResponse
    int recordsAdded = LocalDBUtils.BulkInsertRedemptions(redemptionsList.redemptions);
    totalRecordsAdded += recordsAdded;
    moreRecordsExist = (recordsToFetch > (totalRecordsAdded));
    lastIdFetched = id;
} while (moreRecordsExist);