我怎樣才能讓一個類，用於創建和另一個類

Question

這是我的理解，我可以實現在C＃中單件模式提供接入負全責：

public class ChesneyHawkes{ 
    private static ChesneyHawkes _instance = new ChesneyHawkes(); 
    public ChesneyHawkes Instance {get{return _instance;}} 

    private ChesneyHawkes() 
    { 
    } 

} 

如果我想提供的單個實例一個對象，以至於只能有一個，公開訪問它的對象，但只允許它被創建或被另一個單例替代。

// The PuppetMaster should be the only class that 
// can create the only existing Puppet instance. 

public class PuppetMaster{ 

    private static PuppetMaster_instance = new PuppetMaster(); 
    public static PuppetMaster Instance {get{return _instance;}} 

    // Like a singleton but can be replaced at the whim of PuppetMaster.Instance 
    public static Puppet PuppetInstance {get {return Puppet;}} 

    private PuppetMaster() 
    { 

    } 

    public class Puppet{ 
      // Please excuse the pseudo-access-modifier 
      puppetmasteronly Puppet(){ 

      } 
    } 
} 


// To be accessed like so. 
PuppetMaster.Puppet puppet = PuppetMaster.Instance.PuppetInstance; 

Answer 1

你並不真的需要超過一個單身。看看這個例子：

using System; 

// interface for the "inner singleton" 
interface IPuppet { 
    void DoSomething(); 
} 

class MasterOfPuppets { 

    // private class: only MasterOfPuppets can create 
    private class PuppetImpl : IPuppet { 
     public void DoSomething() { 
     } 
    } 

    static MasterOfPuppets _instance = new MasterOfPuppets(); 

    public static MasterOfPuppets Instance { 
     get { return _instance; } 
    } 

    // private set accessor: only MasterOfPuppets can replace instance 
    public IPuppet Puppet { 
     get; 
     private set; 
    } 
} 

class Program { 
    public static void Main(params string[] args) { 
     // access singleton and then inner instance 
     MasterOfPuppets.Instance.Puppet.DoSomething(); 
    } 
}