private void TaskForm_FormClosing(object sender, FormClosingEventArgs e)
{
if (!task.IsCompleted)
{
if (!cancellationTokenSource.IsCancellationRequested)
{
Cancel();
}
e.Cancel = true;
return;
}
appender.Close();
((Hierarchy)log4net.LogManager.GetRepository()).Root.RemoveAppender(appender);
}