backgroundWorker.ProgressChanged event fires too fast

Question

I've got method:

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
     if (!backgroundWorker1.CancellationPending)
     {
         Ctransakcja obj = (Ctransakcja)e.UserState;
         string[] row = new string[] { obj.id.ToString(), obj.tytul, obj.kwota, obj.nrkonta,obj.bank };
         dataGridView2.Rows.Add(row); 
     }
}

this method adds rows to datagridview. in dowork event of backgroundworker i call method LoadData which connects to database and fire ReportProgress event.

LoadData:

...
while (reader.Read())
{
   obj.id = int.Parse(reader[0].ToString());
   obj.tytul = reader[1].ToString();
   obj.kwota = reader[2].ToString();
   obj.nrkonta = reader[3].ToString();
   obj.bank = reader[4].ToString();
   //dodanie danych itd
   backgroundWorker1.ReportProgress(i, obj);
   i++;
  // Thread.Sleep(100);
}
...

Everything works with Thread.Sleep(100) , but without sleep dates in datagridview are mixed and reproduced. I need some WAIT function to check that row is added and call next report progress on next row from database.

thanks

Answer 1

The ReportProgress event really shouldnt be used to bind your data. It's more for updating a UI control with progress. Bind your data in the background thread, using Invoke()

while (reader.Read())
{
   obj.id = int.Parse(reader[0].ToString());
   obj.tytul = reader[1].ToString();
   obj.kwota = reader[2].ToString();
   obj.nrkonta = reader[3].ToString();
   obj.bank = reader[4].ToString();
   //dodanie danych itd


   dataGridView2.Invoke((MethodInvoker) delegate { dataGridView2.Rows.Add(obj);});

}