Dropdown fields are not displaying but data is on the grid

Hi Team

I need some help, have a combo box, it suppose when loading the application it loads the recipe codes name on the combo box, but its not but the data is on the grid fine. Maybe there is a property that is conflicting with this. Below is my logic

// back end logic

 private void cbxRecipe_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            LoadRecipe();
        }

        public void LoadRecipe()
        {
            TotalCrudeOilPerc = 0;
            CrudeOilPerc = 0;

            CollectionViewSource _StockCodeList = new CollectionViewSource();
            _StockCodeList = (CollectionViewSource)this.FindResource("StockCode");

            CollectionViewSource _StockDescList = new CollectionViewSource();
            _StockDescList = (CollectionViewSource)this.FindResource("StockDescription");

            Managers.BatchMaterialManager.SetAdriotConnection();
            presenter.loadIngredients(Convert.ToInt32(cbxRecipe.SelectedValue), _StockCodeList, _StockDescList);
            presenter.PopulateTotals();
            presenter.loadRecipe(Convert.ToInt32(cbxRecipe.SelectedValue));

            string LastDigit = RecipeName.Substring(4, 1).ToString();
            if (LastDigit == "2") // Has both oils in - allow split
            {
                txtPPATK601.IsReadOnly = false;
            }

        }