hello guys.. I'm mega in Indonesia. sorry for my english so bad..  I have script like : 
 
 private void btnDelete_Click(object sender, EventArgs e)
        {
            if (idx != -1)
            {
                
                int yy = Int32.Parse(txtTotal1.Text);
                int ap = yy - Convert.ToInt16(arTotal[idx].ToString());
                txtTotal1.Text = ap.ToString();
                arId.RemoveAt(idx);
                arNama.RemoveAt(idx);
                arHarga.RemoveAt(idx);
                arBanyak.RemoveAt(idx);
                arTotal.RemoveAt(idx);
            }
            listView1.Items.Clear();
            for (int i = 0; i < this.arId.Count; i++)
            {
                listView1.Items.Add(new ListViewItem(new string[] { arId[i].ToString(), arNama[i].ToString(), arHarga[i].ToString(), arBanyak[i].ToString(), arTotal[i].ToString() }));
            }
        }
 
but error in "int ap = yy - Convert.ToInt16(arTotal[idx].ToString());" can you help me ?