private void paybtn_Click(object sender, EventArgs e)
{
fee = new Fee();
lastBal = fee.CalculateBalance(int.Parse(balancetxt.Text), int.Parse(amttxt.Text));
if (lastBal != -1)
{
FillData();
if (fee.insert())
{
MessageBox.Show("Fee Paid", "Fee Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
DisableAll();
}
}
}