public static void Parse <T1, T2>(
BackgroundWorker worker,
string[] filePaths,
string name,
FilterRowAndGetProductName <T1, T2> FilterRowAndGetProductName,
FilterRows <T1, T2> FilterRows,
out string productName,
out List <T2> records)
where T1 : class
{
productName = null;
records = new List <T2>();
worker.ReportProgress(0);
for (int i = 0; i < filePaths.Length; i++)
{
if (worker.CancellationPending)
{
productName = null;
records = null;
return;
}
try
{
using (TextReader textReader = new StreamReader(filePaths[i]))
{
var engine = new FileHelperAsyncEngine <T1>();
using (engine.BeginReadStream(textReader))
{
// Parse the first row from input CSV file
T1 csvRow = engine.ReadNext();
if (csvRow == null)
{
// There is no data rows in this CSV file -- just skip it
continue;
}
// Remove extra columns and get the product name
string thisProductName;
T2 filteredRow = FilterRowAndGetProductName(csvRow, out thisProductName);
// Check the product name consistency
if (productName != null && thisProductName != productName)
{
string msg = string.Format(
"The selected {0} CSV File(s) do not conform to each other by \"ProductName\" column.",
name);
MessageBox.Show(
msg,
formText,
MessageBoxButtons.OK,
MessageBoxIcon.Error);
productName = null;
records = null;
return;
}
// Save the first row data
productName = thisProductName;
records.Add(filteredRow);
// Parse all other rows from the CSV file lazily
IEnumerable <T1> csvRows = engine.AsEnumerable <T1>();
// Remove extra columns lazily
IEnumerable <T2> filteredRows = FilterRows(csvRows);
// Add new rows to the common list
records.AddRange(filteredRows);
}
}
}
catch (Exception ex)
{
MessageBox.Show(
ex.Message,
formText,
MessageBoxButtons.OK,
MessageBoxIcon.Error);
productName = null;
records = null;
return;
}
worker.ReportProgress(i + 1);
}
}