Inside C#(一些内部实现的东西)

ILDASM是个好的工具,平时也很喜欢用,它能帮助我更好的了解NET。以下我的总结,请执教。

You write:

public enum Compression {

   Zip, SuperZip, None

 }

The C# compiler generates:

public struct Compression : Enum {

   public int value__;

   public const Compression Zip = 0;

   public const Compression SuperZip = 1;

   public const Compression None = 2;

}
What can we learn:
1)Enums 是struct ,内部成员即是struct 也是Enum 。
2)Enum 继承System.Enum 的,structs可以继承ValueType,也可以是Enum 。
3)Enum 内部成员默认是Int的。
4)变量含有”__“的不能使用。
5)所有的值都是const 的,因此在没有重新编译的时候是不能改变的,而且也是类型安全的。
 

You write:

public class Resource

{

   ~Resource() {

      ...

   }

}

The C# compiler generates:

public class Resource

{

   protected override void Finalize() {

      try {

         ...

      }

      finally {

         base.Finalize();

      }

   }

}

What can we learn:
1)解析函数是重写基类的finalize 的。且是不确定的。
2)method (represented by the “…”)是放在Try里,无论有没有异常都会调用基类的finalize 。

You write:

using (Resource res = new Resource()) {

   res.DoWork();

}

The C# compiler generates:

Resource res = new Resource(...);

try {

   res.DoWork();

}

finally {

   if (res != null)
      ((IDisposable)res).Dispose();

}

What can we learn:

使用using 会被编译成try,且会始终执行Dispose方法(基于CLR的异常)。

You write:

object x = ... ;

lock (x) {

   // critical section

}

The C# compiler generates:

System.Threading.Monitor.Enter(x);
try {
   // critical section
}
finally {
   System.Threading.Monitor.Exit(x);
}

What can we learn:
1)       Lock just uses Monitor.Enter and Exit… reading those docs give you a good idea of what is really happening here.
2)       We see our friend try..finally again. This time ensuring that the monitor is exited even if an exception is thrown in the critical section

You write:
ArrayList list = new ArrayList();
foreach(int x in list) { // do nothing }

The C# compiler generates:
ArrayList list1;
int num1;
IEnumerator enumerator1;
IDisposable disposable1;
list1 = new ArrayList();
enumerator1 = list1.GetEnumerator();
try { 
        while (enumerator1.MoveNext()) { 
            num1 = ((int) enumerator1.Current);
         } 
        return;
 }
finally { 
            disposable1 = (enumerator1 as IDisposable); 
            if (disposable1 != null) { 
                    disposable1.Dispose(); 
                }
}

posted on 2008-03-04 11:36 gjcn 阅读(...) 评论(...) 编辑 收藏

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