问ArrayList/List是线程安全的集合吗？如果不是，你怎么让它线程安全呢？

EN

using System;
using System.Collections;
public class SamplesArrayList  
{
   public static void Main()  
   {      
      // Creates and initializes a new ArrayList. It is thread safe ArrayList
      ArrayList myAL = new ArrayList();
      myAL.Add( "The" );
      myAL.Add( "quick" );
      myAL.Add( "brown" );
      myAL.Add( "fox" );

      // Creates a synchronized wrapper around the ArrayList.
      ArrayList mySyncdAL = ArrayList.Synchronized(myAL);

      // Displays the sychronization status of both ArrayLists.
      Console.WriteLine( "myAL is {0}.", myAL.IsSynchronized ? "synchronized" : "not synchronized" );
      Console.WriteLine( "mySyncdAL is {0}.", mySyncdAL.IsSynchronized ? "synchronized" : "not synchronized" );

   }
}