Inside C#(一些內部實現的東西)

ILDASM是個好的工具，平時也很喜歡用，它能協助我更好的瞭解NET。以下我的總結，請執教。

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 ，內部成員即是struct 也是Enum 。
2）Enum 繼承System.Enum 的，structs可以繼承ValueType,也可以是Enum 。
3）Enum 內部成員預設是Int的。
4）變數含有”__“的不能使用。
5）所有的值都是const 的，因此在沒有重新編譯的時候是不能改變的，而且也是型別安全的。
 

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）解析函數是重寫基類的finalize 的。且是不確定的。
2）method (represented by the “…”)是放在Try裡，無論有沒有異常都會調用基類的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 會被編譯成try，且會始終執行Dispose方法（基於CLR的異常）。

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(); 
                }
}