protected void DropDownList4_SelectedIndexChanged(object sender, EventArgs e) { DropDownList5.Items.Clear(); DropDownList5.Items.Add(new ListItem("--Select--", "0")); int medicineType = Convert.ToInt32(DropDownList4.SelectedValue); Doctor_GetMedicineNameByTypeBL objGetMedicineNameByTypeBL = new Doctor_GetMedicineNameByTypeBL(); DropDownList5.DataSource = objGetMedicineNameByTypeBL.Doctor_GetMedicineNameByType(medicineType); DropDownList5.DataTextField = "MEDICINE_NAME"; DropDownList5.DataValueField = "ID"; DropDownList5.DataBind(); }