CSharp7PatternMatch.cs

public void PaymentMethod(object o)
{
    switch (o)
    {
        case string s when s.Contains("CashOnDelivery"):
            Console.WriteLine("cash on delivery");
            break;
        case Paypal pId when pId.Id != null:
            Console.WriteLine($"paypal {pId.Id}");
            break;
        case Card card when card.IsValidCardNumber():
            Console.WriteLine($"Card {card.Number} - {card.Type}");
            break;
    }
}