protected void itemDropDownList_SelectedIndexChanged(object sender, EventArgs e) { if (itemDropDownList.SelectedIndex != 0) { int companyId = Convert.ToInt32(companyDropDownList.SelectedItem.Value); int itemId = Convert.ToInt32(itemDropDownList.SelectedItem.Value); reorderTextBox.Text = stockInManager.GetReorderLevelById(companyId, itemId).ToString(); availableQuantityTextBox.Text = stockInManager.GetQuantityById(companyId, itemId).ToString(); } else { reorderTextBox.Text = availableQuantityTextBox.Text = ""; } stockInTextBox.Text = ""; }