ThreadingEx05_Lock.cs

public class SharedStateDemo
{
    private int itemCount = 0;    
    private object locker = new Object(); // 用於獨佔鎖定的物件

    public void Run()
    {
        var t1 = new Thread(AddToCart);
        var t2 = new Thread(AddToCart);

        t1.Start(300);
        t2.Start(100);
    }

    private void AddToCart(object simulateDelay)
    {
        Console.WriteLine("Enter thread {0}", // 顯示目前所在的執行緒編號
            Thread.CurrentThread.ManagedThreadId); 
        lock (locker)  // 利用 locker 物件來鎖定程式區塊
        {
            itemCount++;

            Thread.Sleep((int)simulateDelay);
            Console.WriteLine("Items in cart: {0} on thread {1}",
                itemCount, Thread.CurrentThread.ManagedThreadId);
        }
    }
}