private void BeginExecuteReader(FillDataParam state)
{
Log("Running FileAsync...");
OpenSelectConnection();
Log("Beginning the asynchronous execution of the reader...");
((SqlCommand)SelectCommand).BeginExecuteReader(Execute, state);
}
private void Execute(IAsyncResult result)
{
Log("Starting FillAsync invoke...");
FillDataParam fillData = (FillDataParam)result.AsyncState;
try
{
IsExecuting = true;
fillData.DataReader = ((SqlCommand)SelectCommand).EndExecuteReader(result);
MinimalDataReader minimalReader = new MinimalDataReader(fillData.DataReader);
Log("Starting initial table fills...");
if (fillData.DataSet != null)
{
Fill(fillData.DataSet, fillData.SourceTableName, minimalReader, 0, PageSize);
}
else
{
Fill(fillData.DataTables, minimalReader, 0, PageSize);
}
if (FillInitialized != null)
{
FillInitialized(fillData);
if (fillData.Cancel)
{
return; // Don't start the data retrieval
}
}
Log("Creating new background worker...");
if (_workerThread != null)
{
Log("Disposing former background worker...");
_workerThread.DoWork -= new DoWorkEventHandler(FillDataSet);
_workerThread.RunWorkerCompleted -= new RunWorkerCompletedEventHandler(CompleteFillDataSet);
_workerThread.Dispose();
}
_workerThread = new BackgroundWorker();
_workerThread.DoWork += new DoWorkEventHandler(FillDataSet);
_workerThread.RunWorkerCompleted += new RunWorkerCompletedEventHandler(CompleteFillDataSet);
_workerThread.WorkerSupportsCancellation = true;
Log("Starting new background worker...");
_workerThread.RunWorkerAsync(fillData);
}
catch (Exception ex)
{
// Save the exception
fillData.Error = ex;
CompleteFillDataSet(this, new RunWorkerCompletedEventArgs(fillData, null, false));
}
}
private void FillDataSet(object sender, DoWorkEventArgs e)
{
Log("Starting FillDataSet invoke...");
FillDataParam fillData = (FillDataParam)e.Argument;
try
{
int startRecordIndex = fillData.StartRecord;
int recordCount = 0;
Log("Starting internal fill while loop...");
while (!fillData.DataReader.IsClosed && !_workerThread.CancellationPending)
{
bool fillCompleted = false;
try
{
Log("Filling tables...");
if (fillData.DataSet != null)
{
recordCount = Fill(fillData.DataSet, fillData.SourceTableName, fillData.DataReader, 0, PageSize);
}
else
{
recordCount = Fill(fillData.DataTables, fillData.DataReader, 0, PageSize);
}
Log($"Tables filled. Record count={recordCount}");
fillCompleted = recordCount == 0 || recordCount != PageSize;
Log($"Fill completed boolean={fillCompleted}");
if (FillDataChunk != null)
{
FillDataChunk(fillData, startRecordIndex, recordCount);
if (fillData.Cancel)
{
_workerThread.CancelAsync();
SelectCommand.Cancel();
fillCompleted = true;
}
}
startRecordIndex += recordCount;
Log($"Next start instance: {startRecordIndex}");
}
catch (Exception ex)
{
fillCompleted = true;
throw new InvalidOperationException("Failed to fill data chunk.", ex);
}
finally
{
Log($"Closing resources.");
if (fillData.DataReader != null && fillCompleted)
{
fillData.DataReader.Close();
}
if (SelectCommand.Connection != null)
{
SelectCommand.Connection.Close();
}
}
}
IsExecuting = false;
}
catch (Exception ex)
{
fillData.Error = ex;
}
finally
{
e.Result = fillData;
}
}
