public static async Task <ICollection <StockData> > ParseStockDataFromFile(string fileName, LoadingProgress progress)
{
StreamReader reader = null;
progress.Reset();
try
{
reader = new StreamReader(fileName);
var data = await reader.ReadToEndAsync();
var lines = await Task.Run(() => data.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries));
var headerRow = lines[0];
var dataRows = lines.Skip(1);
progress.SetEnd(lines.Length - 1);
Regex csvPattern = new Regex(",(?=(?:[^\"]*\"[^\"]*\")*(?![^\"]*\"))");
var headers = csvPattern.Split(headerRow);
Dictionary <string, int> columnIndexes = new Dictionary <string, int>(headers.Length);
for (int i = 0; i < headers.Length; i++)
{
columnIndexes.Add(headers[i].Trim().ToLower(), i);
}
var stockDataList = new ConcurrentBag <StockData>();
Parallel.ForEach(dataRows,
() => new List <StockData>(),
(row, loop, subList) =>
{
System.Threading.Thread.Sleep(1); // to make the loading progress more visible
progress.Progress(1);
var columns = csvPattern.Split(row);
StockData newData = new StockData();
newData.CompanySymbol = columns[columnIndexes["symbol"]].Replace("\"", "");
newData.Date = DateTime.Parse(columns[columnIndexes["date"]].Replace("\"", ""));
newData.PriceAtOpen = decimal.Parse(columns[columnIndexes["open"]].Replace("\"", ""), NumberStyles.Any);
newData.HighPrice = decimal.Parse(columns[columnIndexes["high"]].Replace("\"", ""), NumberStyles.Any);
newData.LowPrice = decimal.Parse(columns[columnIndexes["low"]].Replace("\"", ""), NumberStyles.Any);
newData.PriceAtClose = decimal.Parse(columns[columnIndexes["close"]].Replace("\"", ""), NumberStyles.Any);
var list = subList as List <StockData>;
list.Add(newData);
return(subList);
},
(finalResult) =>
{
Parallel.ForEach(finalResult, (result) => { stockDataList.Add(result); });
});
return(stockDataList.ToList());
}
catch { throw; }
finally
{
reader?.Dispose();
}
}