public void LoadDropdowns()
        {
            DataTable products = stockBLL.GetAllProducts();

            DataRow emptyRow = products.NewRow();

            emptyRow["ProductId"]   = 0;
            emptyRow["ProductName"] = "";
            products.Rows.Add(emptyRow);


            comboBox1.DataSource    = products;
            comboBox1.DisplayMember = "ProductName";
            comboBox1.ValueMember   = "ProductID";

            comboBox1.SelectedValue = 0;

            DataTable make = stockBLL.GetAllMake();

            DataRow emptyRow2 = make.NewRow();

            emptyRow2["make"] = "";
            make.Rows.Add(emptyRow2);
            comboBox2.DataSource    = make;
            comboBox2.ValueMember   = "make";
            comboBox2.DisplayMember = "make";
            comboBox2.SelectedValue = "";
        }