protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { if (DropDownList1.SelectedValue == "0") { Label2.Text = "XXX"; } Button1.CommandArgument = DropDownList1.SelectedItem.ToString(); dml ob = new dml(); DataTable dt = new DataTable(); dt = ob.getsubmodeldetails_label(DropDownList1.SelectedValue.ToString(), submodelid); if (dt.Rows.Count > 0) { Label2.Text = dt.Rows[0]["PRICE"].ToString(); } }