Net复习笔记：第六部分：using关键字

Using一般作用是

1. 引入命名空间using system
2. 创建别名 using alias=namespace | type（using MsWord=Microsoft.office.Interop.Word）
3. 强制资源管理using(){}
4. Using在编译时会被换成（try-finally）
5. Using在做资源管理的时候适合做单一非托管资源管理，多个的话建议使用try
6. Using只能适用于实现了IdisPosable接口的对象

类型转化

1. explicit用于声明必须强制转化的自定义类型
2. implicit用于声明隐私的自定义类型转化
3. public partial class WebForm8 : System.Web.UI.Page
4.     {
5.         protected void Page_Load(object sender, EventArgs e)
6.         {
7.             MyAge age = new MyAge();
8.             int bornAge = (int)age;
9.             Response.Write(bornAge+"<br>");
10.             age = DateTime.Now.Year;
11.             Response.Write(age + "<br>");
12.             Response.Write(age);
13.         }
14.     }
15.     class MyAge
16.     {
17.         private int age = 0;
18.         public int Age
19.         {
20.             get { return age; }
21.             set { age = value; }
22.         }
23.  
24.         public MyAge()
25.         {
26.         
27.         }
28.  
29.         private MyAge(int age)
30.         {
31.             this.age = age;
32.         }
33.  
34.         public static implicit operator MyAge(int year)
35.         {
36.             return new MyAge(year);
37.         }
38.  
39.         public static explicit operator int(MyAge age)
40.         {
41.             return age.Age;
42.         }
43.  
44.         public static implicit operator string(MyAge age)
45.         {
46.             return "你?的Ì?年¨º龄¢?：êo" + age.Age.ToString();
47.         }
48.     }
49.