书接上文。。。
先来看一眼这个AmountFor方法
1 private int AmountFor(Performance aPerformance, Play play)
2 {
3 int result;
4 switch (play.type)
5 {
6 case "tragedy":
7 result = 40000;
8 if (aPerformance.audience > 30)
9 {
10 result += 1000 * (aPerformance.audience - 30);
11 }
12
13 break;
14 case "comedy":
15 result = 30000;
16 if (aPerformance.audience > 20)
17 {
18 result += 1000 + 500 * (aPerformance.audience - 20);
19 }
20
21 break;
22 default:
23 throw new Exception($"unknown type:{play.type}");
24 }
25
26 return result;
27 }
View Code
直觉上这个参数是不是有点问题...按理说演出Performance应该是带有剧目Play信息的（至少带有playid,我们可以添加一个方法通过这个playid获取）,不需要再额外传一个play给方法。所以我们去掉这个play参数.这里用到一个重构手法：以查询替代临时变量
1 private Play PlayFor(Performance aPerformance)
2 {
3 return _plays[aPerformance.playID];
4 }
View Code
所以AmoutFor成了这样
1 private int AmountFor(Performance aPerformance)
2 {
3 int result;
4 switch (PlayFor(aPerformance).type)
5 {
6 case "tragedy":
7 result = 40000;
8 if (aPerformance.audience > 30)
9 {
10 result += 1000 * (aPerformance.audience - 30);
11 }
12
13 break;
14 case "comedy":
15 result = 30000;
16 if (aPerformance.audience > 20)
17 {
18 result += 1000 + 500 * (aPerformance.audience - 20);
19 }
20
21 break;
22 default:
23 throw new Exception($"unknown type:{PlayFor(aPerformance).type}");
24 }
25
26 return result;
27 }
View Code
调用的地方也成了这样
int thisAmount = AmountFor(perf);
再想一想,在Statement方法内部thisAmount是不是可以用AmountFor方法替代,play也可以用PlayFor方法替代.不需要这两个变量了.在需要的地方直接用这两个方法替换.这个重构方法叫：内联变量
所以代码编程这样
1 public string Statement()
2 {
3 int totalAmount = 0;
4 int volumeCredits = 0;
5 string result = $"Statement for {_invoice.Customer} \n";
6 NumberFormatInfo nfi = new CultureInfo("en-US").NumberFormat;
7 nfi.CurrencyDecimalDigits = 2;
8
9 foreach (var perf in _invoice.performances)
10 {
11 //add volume credits
12 volumeCredits += Math.Max(perf.audience - 30, 0);
13 //add extra credit for every ten comedy attendees
14 if ("comedy" == PlayFor(perf).type)
15 {
16 volumeCredits += perf.audience / 5;
17 }
18
19 //print line for this order
20 result += $"{PlayFor(perf).name}: {string.Format(nfi, "{0:C}", AmountFor(perf) / 100)}({perf.audience}seats)\n";
21 totalAmount += AmountFor(perf);
22 }
23
24 result += $"Amount owed is {string.Format(nfi, "{0:C}", totalAmount / 100)}\n";
25 result += $"You earned {volumeCredits} credits \n";
26 return result;
27 }
View Code
现在这个Statement方法是不是已经比原始版本看上去短多啦！foreach里面就干了三件事，算积分，拼接输出字符串，算总金额。算积分的逻辑在这里显的格格不入
接下来，还要做一件事，就是把处理积分的逻辑分离出来，单独提炼出一个方法
1 private int VolumeCreditsFor(Performance perf)
2 {
3 int result = Math.Max(perf.audience - 30, 0);
4 if ("comedy" == PlayFor(perf).type)
5 {
6 result += perf.audience / 5;
7 }
8
9 return result;
10 }
View Code
所以现在看foreach里面直接三个+=是不是统一和谐了
1 public string Statement()
2 {
3 int totalAmount = 0;
4 int volumeCredits = 0;
5 string result = $"Statement for {_invoice.Customer} \n";
6 NumberFormatInfo nfi = new CultureInfo("en-US").NumberFormat;
7 nfi.CurrencyDecimalDigits = 2;
8
9 foreach (var perf in _invoice.performances)
10 {
11 volumeCredits += VolumeCreditsFor(perf);
12 //print line for this order
13 result += $"{PlayFor(perf).name}: {string.Format(nfi, "{0:C}", AmountFor(perf) / 100)}({perf.audience}seats)\n";
14 totalAmount += AmountFor(perf);
15 }
16
17 result += $"Amount owed is {string.Format(nfi, "{0:C}", totalAmount / 100)}\n";
18 result += $"You earned {volumeCredits} credits \n";
19 return result;
20 }
View Code
本篇完成...待续....
标签：重构,int,perf,C#,aPerformance,案例,audience,result,AmountFor From： https://www.cnblogs.com/flylittlebaby/p/17203031.html