void MainFormLoad(object sender, EventArgs e)
{
LoadData();
//on product selected
lstProductList.SelectedValueChanged += delegate {
Product product = lstProductList.SelectedItem as Product;
txtOpeningStock.Text = (product.Stock).ToString();
txtQty.Text = product.Stock.ToString();
txtProductName.Text = product.Name;
};
//on add button clicked
btnAdd.Click += delegate {
string productName = txtProductName.Text.Trim().ToUpper();
int totalStock = 0;
int.TryParse(txtOpeningStock.Text, out totalStock);
Product product = new Product(productName, totalStock);
_stockManager.AddProduct(product);
};
}