protected void companyDropDownList_SelectedIndexChanged(object sender, EventArgs e) { if (companyDropDownList.SelectedIndex != 0) { int companyId = Convert.ToInt32(companyDropDownList.SelectedItem.Value); itemDropDownList.DataSource = stockInManager.GetItemsByCompanyId(companyId); itemDropDownList.DataTextField = "Name"; itemDropDownList.DataValueField = "Id"; itemDropDownList.DataBind(); } else { itemDropDownList.Items.Clear(); } itemDropDownList.Items.Insert(0, "Select Item"); reorderTextBox.Text = availableQuantityTextBox.Text = stockInTextBox.Text = ""; }