using关键字

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 
 6 namespace DisposeAndUsing
 7 {
 8     class Program
 9     {
10         public class A : IDisposable
11         {
12             private bool disposed = false;
13             private void Dispose(bool disposing)
14             {
15                 if (!disposed)
16                 {
17                     if (disposing)
18                     {
19 
20                     }
21                     Console.WriteLine("Cleaning up object");
22                     disposed = true;
23                 }
24             }
25 
26             public void Dispose()
27             {
28                 Dispose(true);
29                 GC.SuppressFinalize(this);
30             }
31 
32             public void DoSomething()
33             {
34                 Console.WriteLine("A.SoSomething()");
35             }
36 
37             ~A()
38             {
39                 Console.WriteLine("Finalizing");
40                 Dispose(false);
41             }
42         }
43 
44         static void Main(string[] args)
45         {
46             using (A a = new A())
47             {
48                 a.DoSomething();
49             }
50 
51             using (A a = new A(), b = new A())
52             {
53                 a.DoSomething();
54                 b.DoSomething();
55             }
56             Console.ReadLine();
57         }
58     }
59 }