在我的Web应用程序中,我对所有在线用户都有以下通用的objectList.

public static List<MyClass> myObjectList = new List<MyClass>();

因此,当多个在线用户尝试从此对象myObjectList读取数据时,就有可能发生线程同步问题.

在另一种情况下,多个用户正在从myObjectList进行读取,而其中很少有人也在写入,但是每个用户都在List的不同索引上进行写入.每个用户都可以在此列表中添加一个新项目.所以现在我认为有同步问题的机会.

如何编写线程安全实用程序类,该类可以以更安全的方式从该对象读取和写入数据.

非常欢迎提出建议

Angelo建议的代码如下所示

using System;
using System.Collections.Concurrent;
using System.Threading;
using System.Threading.Tasks;


namespace ObjectPoolExample
{
    public class ObjectPool<T>
    {
        private ConcurrentBag<T> _objects;
        private Func<T> _objectGenerator;

        public ObjectPool(Func<T> objectGenerator)
        {
            if (objectGenerator == null) throw new ArgumentNullException("objectGenerator");
            _objects = new ConcurrentBag<T>();
            _objectGenerator = objectGenerator;
        }

        public T GetObject()
        {
            T item;
            if (_objects.TryTake(out item)) return item;
            return _objectGenerator();
        }

        public void PutObject(T item)
        {
            _objects.Add(item);
        }
    }

    class Program
    {
       static void Main(string[] args)
        {
            CancellationTokenSource cts = new CancellationTokenSource();

            // Create an opportunity for the user to cancel.
            Task.Factory.StartNew(() =>
                {
                    if (Console.ReadKey().KeyChar == 'c' || Console.ReadKey().KeyChar == 'C')
                        cts.Cancel();
                });

            ObjectPool<MyClass> pool = new ObjectPool<MyClass> (() => new MyClass());            

            // Create a high demand for MyClass objects.
            Parallel.For(0, 1000000, (i, loopState) =>
                {
                    MyClass mc = pool.GetObject();
                    Console.CursorLeft = 0;
                    // This is the bottleneck in our application. All threads in this loop
                    // must serialize their access to the static Console class.
                    Console.WriteLine("{0:####.####}", mc.GetValue(i));                 

                    pool.PutObject(mc);
                    if (cts.Token.IsCancellationRequested)
                        loopState.Stop();                 

                });
            Console.WriteLine("Press the Enter key to exit.");
            Console.ReadLine();
        }

    }

    // A toy class that requires some resources to create.
    // You can experiment here to measure the performance of the
    // object pool vs. ordinary instantiation.
    class MyClass
    {
        public int[] Nums {get; set;}
        public double GetValue(long i)
        {
            return Math.Sqrt(Nums[i]);
        }
        public MyClass()
        {
            Nums = new int[1000000];
            Random rand = new Random();
            for (int i = 0; i < Nums.Length; i++)
                Nums[i] = rand.Next();
        }
    }   
}

我想我可以采用这种方法.

解决方法:

如果您使用的是.NET 4.0,最好更改为运行时已支持的thread-safe collections之一,例如ConcurrentBag.

但是,如果我没记错的话,并发包不支持按索引访问,因此,如果需要通过给定键访问对象,则可能需要求助于ConcurrentDictionary.

如果不能使用.NET 4.0,则应阅读以下博客文章：

Why are thread safe collections so hard?