/// <summary>
/// Add an item to a transaction.
/// </summary>
/// <param name="transaction">Transaction to add an item to.</param>
/// <param name="code">Product code or SKU.</param>
/// <param name="name">Product name.</param>
/// <param name="price">Unit price.</param>
/// <param name="quantity">Quantity.</param>
/// <param name="variation">Variation or category.</param>
public static void AddItem(this TransactionActivity transaction, string code, string name, decimal price, int quantity, string variation = null)
{
if (transaction == null)
{
throw new ArgumentNullException("transaction");
}
transaction.AddItem(new TransactionItemActivity(code, name, price, quantity, variation));
}