private void btnCalc_Click(object sender, EventArgs e)
{
if ((cmbField.SelectedItem == null) || (cmbAggregateFunction.SelectedItem == null))
{
return;
}
lblResult.Text = Convert.ToString(grid.GetTotal(cmbField.SelectedItem as GridEXColumn, (AggregateFunction)cmbAggregateFunction.SelectedItem));
}