A preliminary study on new features of C # 3.0 PART4: Using the collection type initializer

Collection

Collection type initializer (Collection initializers)

Want to see a "strange" code:
 1class Program
 2    {
 3         static void Main (string[] args)
 4        {
 5             var a = new Point {x = ten, y = 13};
 6            var b = new Point {x =, 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);
One
12            var c = new Point {x =, y =};
13            var r2 = new Rectangle {p2 = c};

15            Console.WriteLine ("R2:p1 = = {0}, P2 = {1}, {2} ',
16                         r2.p1, r2.p2.x, R2.P2.Y);
17       }          
18   }

20    public class point
21    {
22         public int x, y;
23   }
24    public class Rectangle
25    {
26         public point P1, p2;
27   }
Do you notice the initialization syntax for the collection type? Straightforward!
This is also a new feature in the C # 3.0 syntax specification.

Perhaps the following example illustrates the problem more:


This is our previous wording:


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");


keywords. ADD ("switch");


one by one keywords. ADD ("new");


keywords. ADD ("if");


keywords. ADD ("Else");


14}


15


public static bool Iskeyword (string s)


17 {


return keywords. Contains (s);


19}


static void Main (string[] args)


21 {


initkeywords ();


String[] Totest = {"Some", "identifiers", "for", "testing"};


24


foreach (string s in Totest)


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


27}


28}


This is our notation in C # 3.0:


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


static void Main (string[] args)


13 {


String[] Totest = {"Some", "identifiers", "for", "testing"};


15


foreach (string s in Totest)


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


18}

Does the
19} become initialized like an enumeration type?


personally think it's helpful to improve the reading quality of the code,


otherwise a bunch of add () look not concise, feel very long-winded.