狀態模式

狀態模式

狀態模式

狀態模式

主要解決當控制一個物件狀態轉換的條件運算式過於
複雜時的情況。把狀態的判斷邏輯轉移到不同狀態的
一系列類別當中，可以把複雜的判斷邏輯簡化。

abstract class State
{
public abstract void Handle(Context context);
}

class ConcreteStateA : State
{
public override void Handle(Context context)
{
context.State = new ConcreteStateB();
}
}

class ConcreteStateB : State
{
public override void Handle(Context context)
{
context.State = new ConcreteStateA();
}
}

class Context
{
private State state;
public Context(State state)
{
this.state = state;
}

public State State
{
    get { return state; }
    set 
    {
        state = value;
        Console.WriteLine("當前狀態:" + state.GetType().Name);
    }
    
    public void Request()
    {
        state.Handle(this);
    }
}

}

static void Main(string[] args)
{
Context c = new Context(new ConcreteStateA());

c.Request();
c.Request();
c.Request();
c.Request();

Console.Read();

}