protected void BindProductDroDown()
 {
     try
     {
         DataTable dt = us_dll.GetProductDetails();
         if (dt.Rows.Count > 0)
         {
             ddlproduct.DataSource     = dt;
             ddlproduct.DataTextField  = "PRODUCTDESC";
             ddlproduct.DataValueField = "PRODUCTID";
             ddlproduct.DataBind();
             ddlproduct.Items.Insert(0, new ListItem("--Select--", "0"));
         }
     }
     catch (Exception ex)
     {
         ErrorMessage(ex.Message);
     }
 }