// State
// Definition
// Allow an object to alter its behavior when its internal state changes.
// The object will appear to change its class.
// Participants
// The classes and objects participating in this pattern are:
// - Context (Account)
// - defines the interface of interest to clients
// - maintains an instance of a ConcreteState subclass that defines the current state.
// - State (State)
// - defines an interface for encapsulating the behavior associated with a particular state of the Context.
// - Concrete State (RedState, SilverState, GoldState)
// - each subclass implements a behavior associated with a state of Context
/// <summary>
/// Entry point into console application
/// </summary>
static void Main()
{
#region Structural code in C#
// Structural code in C#
// This structural code demonstrates the State pattern which allows an object to behave differently
// depending on its internal state. The difference in behavior is delegated to objects that represent this state.
// Setup context in a state
Structural.Context c = new Structural.Context(new Structural.ConcreteStateA());
// Issue requests, which toggles state
c.Request();
c.Request();
c.Request();
c.Request();
// Wait for user
Console.ReadKey();
#endregion
#region Real-world code in C#
// Real-world code in C#
// This real-world code demonstrates the State pattern which allows an Account to behave differently depending on its balance.
// The difference in behavior is delegated to State objects called RedState, SilverState and GoldState.
// These states represent overdrawn accounts, starter accounts, and accounts in good standing.
// Open a new account
Real.Account account = new Real.Account("Franco Pellegrino");
// Apply financial transactions
account.Deposit(500.0);
account.Deposit(300.0);
account.Deposit(550.0);
account.PayInterest();
account.Withdraw(2000);
account.Withdraw(1100);
// Wait for user
Console.ReadKey();
#endregion
#region MyCode
My.Dichiarazione dich = new My.Dichiarazione(new My.StatoErrata());
dich.Calcola();
dich.Modifica();
dich.Calcola();
dich.Stampa();
// Wait for user
Console.ReadKey();
#endregion
}
public override void Modifica(Dichiarazione context)
{
context.State = new StatoErrata();
}
public override void Stampa(Dichiarazione context)
{
context.State = new StatoStampata();
}
public override void Calcola(Dichiarazione context)
{
context.State = new StatoCompleta();
}
public abstract void Modifica(Dichiarazione context);
public abstract void Stampa(Dichiarazione context);
public abstract void Calcola(Dichiarazione context);