同步类MethodImplAttribute的使用

System.Runtime.ComplierService命名空间包含的一些属性将影响CLR在运行时的行为。
MethodImplAttribute的一个构造函数把MethodImplOption枚举作为其参数。
MethodImplOptions枚举有一个字段Synchronized,它指定在任一时刻只允许一个线程访问这个方法。
但它不处理静态字段和方法的同步。如果必须同步特定代码块，它也不起作用。同步整个对象是对轻松使用必须付出的代价。
示例展示了使用MethodImplAttribute的效果与没有使用同步线程时不一样。

using System;
using System.Threading;
using System.Runtime.CompilerServices;

namespace thread
...{
    public class MethodImpl
    ...{
        class MI
        ...{
                     //This attribute locks the method for use
                     //by one and only one thread at a time.
            [MethodImpl(MethodImplOptions.Synchronized)]
            public void doSomeWorkSync()
            ...{
                Console.WriteLine("doSomeWorkSync()--Lock held by Thread" + Thread.CurrentThread.GetHashCode());
                Thread.Sleep(5 * 1000);
                Console.WriteLine("doSomeWorkSync() --Lock released by Thread" + Thread.CurrentThread.GetHashCode());
            }
                    //This is a non synchronized method
            
            public void doSomeWorkNoSync()
            ...{
                Console.WriteLine("doSomeWorkNoSync()--Entered Thread is" + Thread.CurrentThread.GetHashCode());
                Thread.Sleep(5 * 1000);
                Console.WriteLine("doSomeWorkNoSync()" + Thread.CurrentThread.GetHashCode());
            }

           [STAThread]  
        public static void Main(string[] args)
        ...{
            MI m = new MI();

                //Delegate for Non-Synchronous operation
            ThreadStart tsNoSyncDelegate = new ThreadStart(m.doSomeWorkNoSync);
                //Delegate for Synchronous operation
            ThreadStart tsSyncDelegate =
                new ThreadStart(m.doSomeWorkSync);

                Thread t1=new Thread(tsNoSyncDelegate);
                Thread t2=new Thread(tsNoSyncDelegate);

                t1.Start();
                t2.Start();

                Thread t3 = new Thread(tsSyncDelegate);
                Thread t4 = new Thread(tsSyncDelegate);
                t3.Start();
                t4.Start();
       }
       

            
        }
      
    }
}