示例代码：
class Program { static void Main(string[] args) { Console.WriteLine("Incorrect Counter"); Counter c1 = new Counter(); var t1 = new Thread(() => TestCounter(c1)); //派生类等与实例化后的基类，c1 is CounterBase var t2 = new Thread(() => TestCounter(c1)); var t3 = new Thread(() => TestCounter(c1)); t1.Start(); t2.Start(); t3.Start(); t1.Join(); t2.Join(); t3.Join(); Console.WriteLine("Total Count:{0}", c1.Count); Console.WriteLine("------------------------"); Console.WriteLine("Correct counter"); CounterWithLock c2 = new CounterWithLock(); t1 = new Thread(() => TestCounter(c2)); //派生类等与实例化后的基类，c2 is CounterBase t2 = new Thread(() => TestCounter(c2)); t3 = new Thread(() => TestCounter(c2)); t1.Start(); t2.Start(); t3.Start(); t1.Join(); t2.Join(); t3.Join(); Console.WriteLine("Total Count:{0}", c2.Count); } static void TestCounter(CounterBase c) { for(int i=0;i<10000;i++) { c.Increment(); //增量 c.Decrement(); //减量 } } class Counter : CounterBase { public int Count { get; private set; } //计算后的结果 public override void Decrement() //对定义的抽象方法重写 { Count--; } public override void Increment() { Count++; } } class CounterWithLock : CounterBase { private readonly object _asyncRoot = new object(); public int Count { get; private set; } public override void Decrement() { lock (_asyncRoot) //这里也可以把全局静态变量_asyncRoot改成this { Count--; } } public override void Increment() { lock(_asyncRoot) { Count++; } } } abstract class CounterBase { public abstract void Increment(); //增量函数 public abstract void Decrement(); //减量函数 } }