WebServicePortClient Client = new WebServicePortClient();
Client.Solution_Connect("username", "password");
Client.Solution_SetLanguage(language);
Client.Product_SetFields("Id, Title, Stock, ItemNumber");
Product[] products = Client.Product_GetAll();

foreach (Product myproduct in products)
                {


                    if (myproduct.ItemNumber == "BTL1019")
                    {
                        writeToLog("BTL1019 found");

                        ProductStockUpdate updateProduct = new ProductStockUpdate();
                        updateProduct.Id = myproduct.Id.ToString();
                        updateProduct.Stock = 100;



                        SaveResult[] updatedResults = Client.Product_Update(new sObject[] { updateProduct });



                        if (updatedResults[0].success)
                        {
                            string id = updatedResults[0].id;
                            writeToLog("<br/>ID:" + id);
                            writeToLog("Stock:<br/>" + updateProduct.Stock);
                            writeToLog("<br/>UPDATE Product Successfully!!!");
                        }
                        else
                        {
                            string result = updatedResults[0].errors[0].message;
                           writeToLog("<br/>ERROR:" + result);
                        }
                    }


                    writeToLog(myproduct.ItemNumber + " / " + myproduct.Stock);
                }