C# Keynote

【C# Keynote】

1、 Main 方法必须包含在一个类内，参数类型、返回值类型可以有多种变化。

// Hello1.cs
public class Hello1
{
   public static void Main()
   {
      System.Console.WriteLine("Hello, World!");
   }
}

// Hello3.cs
// arguments: A B C D
using System;

public class Hello3
{
   public static void Main(string[] args)
   {
      Console.WriteLine("Hello, World!");
      Console.WriteLine("You entered the following {0} command line arguments:",
         args.Length );
      for (int i=0; i < args.Length; i++)
      {
         Console.WriteLine("{0}", args[i]); 
      }
   }
}

// Hello4.cs
using System;

public class Hello4
{
   public static int Main(string[] args)
   {
      Console.WriteLine("Hello, World!");
      return 0;
   }
}

2、通过foreach语句来遍历容器。

// cmdline2.cs
// arguments: John Paul Mary
using System;

public class CommandLine2
{
   public static void Main(string[] args)
   {
       Console.WriteLine("Number of command line parameters = {0}",
          args.Length);
       foreach(string s in args)
       {
          Console.WriteLine(s);
       }
   }
}

3、C# 数组从零开始建立索引，声明数组时，方括号 ([]) 必须跟在类型后面，而不是标识符后面。在 C# 中，将方括号放在标识符后是不合法的语法。

 

　　另一细节是，数组的大小不是其类型的一部分，而在 C 语言中它却是数组类型的一部分。这使您可以生成Heap上的数组。

4、声明多维数组，以及数组的数组.

//多维数组
string[,] names;

//数组的数组
byte[][] scores;

int[] numbers = new int[5];
string[,] names = new string[5,4];

//初始化数组的数组
byte[][] scores = new byte[5][];
for (int x = 0; x < scores.Length; x++) 
{
   scores[x] = new byte[4];
}

5、数组的多种初始化.

// 初始化一维数组
int[] numbers = new int[5] {1, 2, 3, 4, 5};
string[] names = new string[3] {"Matt", "Joanne", "Robert"};

int[] numbers = new int[] {1, 2, 3, 4, 5};
string[] names = new string[] {"Matt", "Joanne", "Robert"};

int[] numbers = {1, 2, 3, 4, 5};
string[] names = {"Matt", "Joanne", "Robert"};

// 初始化二维数组
int[,] numbers = new int[3, 2] { {1, 2}, {3, 4}, {5, 6} };
string[,] siblings = new string[2, 2] { {"Mike","Amy"}, {"Mary","Albert"} };

int[,] numbers = new int[,] { {1, 2}, {3, 4}, {5, 6} };
string[,] siblings = new string[,] { {"Mike","Amy"}, {"Mary","Albert"} };

int[,] numbers = { {1, 2}, {3, 4}, {5, 6} };
string[,] siblings = { {"Mike", "Amy"}, {"Mary", "Albert"} };

// 初始化交错数组
int[][] numbers = new int[2][] { new int[] {2,3,4}, new int[] {5,6,7,8,9} };

int[][] numbers = new int[][] { new int[] {2,3,4}, new int[] {5,6,7,8,9} };

int[][] numbers = { new int[] {2,3,4}, new int[] {5,6,7,8,9} };

6、访问数组成员.

int[,] numbers = { {1, 2}, {3, 4}, {5, 6}, {7, 8}, {9, 10} };
numbers[1, 1] = 5;

// 访问交错数组
numbers[0][0] = 58;
numbers[1][1] = 667;

7、在 C# 中，数组实际上是对象。System.Array 是所有数组类型的抽象基类型。多维数组也可以使用foreach来访问.

int[,] numbers = new int[3, 2] {{9, 99}, {3, 33}, {5, 55}};
foreach(int i in numbers)
{
   Console.Write("{0} ", i);
}

8、通过以下方式定义属性.

    private string myName ="N/A";
    private int myAge = 0;

    // Declare a Name property of type string:
    public string Name
    {
        get 
        {
           return myName; 
        }
        set 
        {
           myName = value; 
        }
    }

    // Declare an Age property of type int:
    public int Age
    {
        get 
        { 
           return myAge; 
        }
        set 
        { 
           myAge = value; 
        }
    }

参考：http://msdn.microsoft.com/zh-cn/library/aa288453(v=vs.71).aspx