C# 3.0新特性初步研究 Part4:使用集合类型初始化器_C#教程

集合类型初始化器（Collection Initializers）

想看一段“奇怪”的代码：

1class Program

2 {

3 static void Main(string[] args)

4 {

5 var a = new Point { x = 10, y = 13 };

6 var b = new Point { x = 33, y = 66 };

7

8 var r1 = new Rectangle { p1 = a, p2 = b };

9 Console.WriteLine("r1: p1 = {0},{1}, p2 = {2},{3}",

10 r1.p1.x, r1.p1.y, r1.p2.x, r1.p2.y);

11

12 var c = new Point { x = 13, y = 17 };

13 var r2 = new Rectangle { p2 = c };

14

15 Console.WriteLine("r2: p1 == {0}, p2 = {1}, {2}",

16 r2.p1, r2.p2.x, r2.p2.y);

17 }

18 }

19

20 public class Point

21 {

22 public int x, y;

23 }

24 public class Rectangle

25 {

26 public Point p1, p2;

27 }

注意到集合类型的初始化语法了吗？直截了当！

这也是C# 3.0语法规范中的一个新特性。

也许下面的例子更能说明问题：

这是我们以前的写法：

1class Program

2 {

3 private static List<string> keywords = new List<string>();

4

5 public static void InitKeywords()

6 {

7 keywords.Add("while");

8 keywords.Add("for");

9 keywords.Add("break");

10 keywords.Add("switch");

11 keywords.Add("new");

12 keywords.Add("if");

13 keywords.Add("else");

14 }

15

16 public static bool IsKeyword(string s)

17 {

18 return keywords.Contains(s);

19 }

20 static void Main(string[] args)

21 {
22 InitKeywords();

23 string[] toTest = { "some", "identifiers", "for", "testing" };

24

25 foreach (string s in toTest)

26 if (IsKeyword(s)) Console.WriteLine("'{0}' is a keyword", s);

27 }

28 }

这是我们在C# 3.0中的写法：

1class Program

2 {

3 private static List<string> keywords = new List<string> {

4 "while", "for", "break", "switch", "new", "if", "else"

5 };

6

7 public static bool IsKeyword(string s)

8 {

9 return keywords.Contains(s);

10 }

11

12 static void Main(string[] args)

13 {

14 string[] toTest = { "some", "identifiers", "for", "testing" };

15

16 foreach (string s in toTest)

17 if (IsKeyword(s)) Console.WriteLine("'{0}' is a keyword", s);

18 }

19 }是不是变得像枚举类型的初始化了？

个人觉得这对提高代码的阅读质量是很有帮助的，

否则一堆Add（）看上去不简洁，感觉很啰嗦。
http://zc1984.cnblogs.com/archive/2006/06/10/422705.html