集合类型初始化器（Collection Initializers）
想看一段“奇怪”的代码：
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：
这是我们在C# 3.0中的写法：
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。
想看一段“奇怪”的代码：
1
class 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![]()
}
class Program2
{
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 Point21
{22
public int x, y;23
}24
public class Rectangle25
{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：
1![]()
class 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![]()
}
class Program2
{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：
1![]()
class 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？class Program2
{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
}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。
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