error in displaying in school billing system c#

Question

private void txt_sID_KeyUp(object sender, KeyEventArgs e)

{

txt_name.Text = "";

txtYear.Text = "";

txtSchYear.Text = "";

txt_total.Text = "0.00";

txt_bal.Text = "0.00";

tbl.Items.Clear();

cn = ClassDB.ConnectDB();

cmd = new SqlCommand("SELECT * FROM tblStudentRegistration WHERE lrn='" + txt_sID.Text + "' AND status ='" + "ACTIVE" + "'", cn);

dr = cmd.ExecuteReader();

if (dr.Read())

{

txt_name.Text = dr.GetString(1);

txtYear.Text = dr.GetString(19);

txtSchYear.Text = dr.GetString(22);

try

{

cn = ClassDB.ConnectDB();

cmd = new SqlCommand("SELECT * FROM tblstudpayment WHERE lrn='" + txt_sID.Text + "' ", cn);

dr = cmd.ExecuteReader();

int ctr = 0;

while (dr.Read())

{

ctr++;

}

if (ctr > 0)

{

txt_total.Text = Convert.ToString(dr.GetValue(7))

tbl.Items.Clear();

cn = ClassDB.ConnectDB();

cmd = new SqlCommand("SELECT * FROM tblschoolfee WHERE gradelevel LIKE '" + txtYear.Text + "%' ", cn);

dr = cmd.ExecuteReader();

while (dr.Read())

{

ListViewItem item = new ListViewItem(Convert.ToString(dr.GetValue(0)));

item.SubItems.Add(dr.GetString(2));

item.SubItems.Add(Convert.ToString(dr.GetValue(3)));

tbl.Items.Add(item);

}

}

else

{

cn = ClassDB.ConnectDB();

cmd = new SqlCommand("SELECT * FROM tblschoolfee WHERE gradelevel ='" + txtYear.Text + "' ", cn);

dr = cmd.ExecuteReader();

while (dr.Read())

{

ListViewItem item = new ListViewItem(Convert.ToString(dr.GetValue(0)));

item.SubItems.Add(dr.GetString(2));

item.SubItems.Add(Convert.ToString(dr.GetValue(3)));

tbl.Items.Add(item);

}

decimal gtotal = 0;

foreach (ListViewItem lstItem in tbl.Items)

{

gtotal += decimal.Parse(lstItem.SubItems[2].Text);

}

txt_total.Text = Convert.ToString(gtotal.ToString("###,###,##0.#0"));

}

}

catch (Exception ex)

{

MessageBox.Show(ex.Message);

}

}

}