Error : Index was outside the bounds of the array.

Question

connection.Open();

MySqlCommand cmd_tax = new MySqlCommand("select tax_cat from item_master where cat='1' limit 0,3",connection);

MySqlDataReader dread_tax = cmd_tax.ExecuteReader();

int x = 0;

sub_tot = Convert.ToDouble(textBox5.Text);

while (dread_tax.Read())

{

if (x == 0)

{

x = 1;

ser_tax = ((Convert.ToDouble(dread_tax.GetValue(1).ToString()) / 100) * sub_tot);

textBox10.Text = ser_tax.ToString();

}

else if (x == 1)

{

x = 2;

vat = ((Convert.ToDouble(dread_tax.GetValue(1).ToString()) / 100) * sub_tot);

textBox11.Text = vat.ToString();

}

else

{

sc = ((Convert.ToDouble(dread_tax.GetValue(1).ToString()) / 100) * sub_tot);

textBox15.Text = sc.ToString();

}

}

dread_tax.Close();

connection.Close();