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:
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class Program
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{
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static void Main(string[] args)
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{
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var a = new Point { x = 10, y = 13 };
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var b = new Point { x = 33, y = 66 };
7![](/Images/OutliningIndicators/InBlock.gif)
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var r1 = new Rectangle { p1 = a, p2 = b };
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Console.WriteLine("r1: p1 = {0},{1}, p2 = {2},{3}",
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r1.p1.x, r1.p1.y, r1.p2.x, r1.p2.y);
11![](/Images/OutliningIndicators/InBlock.gif)
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var c = new Point { x = 13, y = 17 };
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var r2 = new Rectangle { p2 = c };
14![](/Images/OutliningIndicators/InBlock.gif)
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Console.WriteLine("r2: p1 == {0}, p2 = {1}, {2}",
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r2.p1, r2.p2.x, r2.p2.y);
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}
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}
19![](/Images/OutliningIndicators/None.gif)
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public class Point
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{
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public int x, y;
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}
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public class Rectangle
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{
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public Point p1, p2;
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}
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![](/Images/OutliningIndicators/ExpandedBlockStart.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/ExpandedBlockEnd.gif)
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
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{
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private static List<string> keywords = new List<string>();
4![](/Images/OutliningIndicators/InBlock.gif)
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public static void InitKeywords()
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{
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keywords.Add("while");
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keywords.Add("for");
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keywords.Add("break");
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keywords.Add("switch");
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keywords.Add("new");
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keywords.Add("if");
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keywords.Add("else");
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}
15![](/Images/OutliningIndicators/InBlock.gif)
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public static bool IsKeyword(string s)
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{
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return keywords.Contains(s);
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}
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static void Main(string[] args)
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{
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InitKeywords();
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string[] toTest = { "some", "identifiers", "for", "testing" };
24![](/Images/OutliningIndicators/InBlock.gif)
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foreach (string s in toTest)
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if (IsKeyword(s)) Console.WriteLine("'{0}' is a keyword", s);
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}
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}
![](/Images/OutliningIndicators/None.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/ExpandedSubBlockEnd.gif)
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![](/Images/OutliningIndicators/ExpandedBlockEnd.gif)
这是我们在C# 3.0中的写法:
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class Program
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{
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private static List<string> keywords = new List<string> {
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"while", "for", "break", "switch", "new", "if", "else"
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};
6![](/Images/OutliningIndicators/InBlock.gif)
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public static bool IsKeyword(string s)
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{
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return keywords.Contains(s);
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}
11![](/Images/OutliningIndicators/InBlock.gif)
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static void Main(string[] args)
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{
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string[] toTest = { "some", "identifiers", "for", "testing" };
15![](/Images/OutliningIndicators/InBlock.gif)
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foreach (string s in toTest)
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if (IsKeyword(s)) Console.WriteLine("'{0}' is a keyword", s);
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}
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}
是不是变得像枚举类型的初始化了?![](/Images/OutliningIndicators/None.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/InBlock.gif)
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![](/Images/OutliningIndicators/ExpandedSubBlockEnd.gif)
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![](/Images/OutliningIndicators/ExpandedBlockEnd.gif)
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。