public static int UpdateUnitCount( 
   Product product,
   int unitCount 
)

class MyPage : System.Web.UI.Page
{
   private Product product;
   public void StockForUnits(Product prod)
   {
       if (Request["saveUnit"] == "1")
       {
           AddProdUnit(prod);

           Dynamicweb.eCommerce.Variants.VariantOptionCollection units = Dynamicweb.eCommerce.Variants.VariantOption.getVariantOptions(prod, 1);
           Product.UpdateUnitCount(prod, units.Count);
       }
   }

   private void AddProdUnit(Product prd)
   {
       string reqName = null;
       string reqValue = null;

       if (Base.ChkNumber(prd.Type) == 0)
       {
           Dynamicweb.eCommerce.Stocks.StockUnit su = new Dynamicweb.eCommerce.Stocks.StockUnit();
           su.Delete(prd.ID);

           foreach (string item in Request.Form)
           {
               reqName = item.ToString();
               reqValue = Request[item];

               if (reqName.IndexOf("PRODUNIT_ID") == 0)
               {
                   if (!string.IsNullOrEmpty(reqValue))
                   {
                       su.ProductID = prd.ID;
                       su.VariantID = "";
                       su.UnitID = reqValue;
                       su.Save(product.ID, "", reqValue);
                   }
               }
           }
       }
   }
}