学步园

首先是组合case标签。

例子如下：

 1using System;
 2
 3enum Tenders : int
 4{
 5    Cash = 1,
 6    Visa,
 7    MasterCard,
 8    AmericanExpress
 9};
10
11class Payment
12{
13    public Payment(Tenders tender)
14    {
15        this.Tender = tender;
16    }
17    
18    protected Tenders tender;
19    public Tenders Tender
20    {
21        get
22        {
23            return this.tender;
24        }
25        set
26        {
27            this.tender = value;
28        }
29    }
30    
31    public void ProcessPayment()
32    {
33        switch((int)(this.tender))
34        {
35            case (int)Tenders.Cash:
36                Console.WriteLine("\nCash - Always good");
37                break;
38                
39            case (int)Tenders.Visa:                
40            case (int)Tenders.MasterCard:
41            case (int)Tenders.AmericanExpress:
42                Console.WriteLine("\nDisplay Credit card Authorization Dialog.");
43                break;
44                
45            default:
46                Console.WriteLine("\nSorry - Invalid tender");
47                break;
48        }
49    }
50}
51
52class Switch
53{
54    public static void DisPlayMenu()
55    {
56        Console.WriteLine("Which form of payment is" + "Being Used:");
57        Console.WriteLine("\t1 = Cash");
58        Console.WriteLine("\t2 = Visa");
59        Console.WriteLine("\t3 = Master Card");
60        Console.WriteLine("\t4 = American Express");
61        Console.WriteLine("===>");
62    }
63    
64    public static int GetTender()
65    {
66        int tenderChoice = -1;
67        DisPlayMenu();
68        
69        bool validTender = false;
70        while(!validTender)
71        {
72            string str = Console.ReadLine();
73            tenderChoice = Convert.ToInt32(str);
74            
75            if(tenderChoice >= 0 && tenderChoice <=4)
76                validTender = true;
77            else
78                Console.WriteLine("Ivalid choice - try again");
79        }
80        
81        return tenderChoice;
82    }
83    
84    public static void Main()
85    {
86        Tenders tenderChoice = (Tenders)GetTender();
87        Payment payment = new Payment(tenderChoice);
88        payment.ProcessPayment();
89        
90        Console.ReadLine();
91    }
92}

  虽然可以组合case标签，但是不能穿透switch语句。
 比如39-43行改成：

            case (int)Tenders.Cash:
                Console.WriteLine("\nCash - Always good");
                
            case (int)Tenders.Visa:
                Console.WriteLine("Visa - Accepted");
                
            case (int)Tenders.MasterCard:
                Console.WriteLine("\nMasterCard - Accepted");
          
                
            case (int)Tenders.AmericanExpress:
                Console.WriteLine("\nAmerican Express - Accepted");
                break;

 

 编译时就会报错。
但是我确实想让它实现贯穿的效果呢？当然还是有其他弯路可以走的：
 第一种方法就是使用if语句替代：

        if(Tenders.Cash = Tenders.Visa)
        {
                Console.WriteLine("\nCash - Always good");
        }
        Console.WriteLine("Visa - Accepted");
      Console.WriteLine("\nMasterCard - Accepted");                
        Console.WriteLine("\nAmerican Express - Accepted");

（当然，这个例子的语义本来就不适合贯穿，仅作演示）

 第二种方法是使用我们一直避讳使用的goto语句：

            case (int)Tenders.Cash:
                Console.WriteLine("\nCash - Always good");
                goto case (int)Tenders.Visa;
                
            case (int)Tenders.Visa:
                Console.WriteLine("Visa - Accepted");
                goto case (int)Tenders.MasterCard;
                
            case (int)Tenders.MasterCard:
                Console.WriteLine("\nMasterCard - Accepted");
                goto case (int)Tenders.AmericanExpress;
                
            case (int)Tenders.AmericanExpress:
                Console.WriteLine("\nAmerican Express - Accepted");
                break;

参考资料：《C#技术揭秘》