Drink.cs

namespace party.foods
{
abstract class Drink
{
string name;

public string Id
{
get
{
return name;
}

set
{
name = value;
}
}

public Drink(string s)
{
Id = s; // calling the set accessor of the Id property
}

override public string ToString()
{
return $"{Id}";
}
}
}

AppParty Cake