public void PopulateMedicineDropdownList()
{
int centerId = Convert.ToInt32(Session["centerId"]);
medicineDropDownList.DataSource = manager.PopulateMedicineDropDownList(centerId);
medicineDropDownList.DataTextField = "MedicineName";
medicineDropDownList.DataValueField = "Serial";
medicineDropDownList.DataBind();
}