使用共享资源创建多个线程

好的，所以我在创建一堆线程并且它们都使用同一对象时遇到了问题。我的想法是我有一个项目的“队列”（又名列表），并且应该逐个处理这些项目，直到所有项目都已处理完毕。当前，这在一个线程上工作得很好（当我更改threadcount = 1时），但是当我尝试将其设置为threadcount = 2且线程竞争时，这一切都变成了一个糟糕的地方。

这是我制作的一些快速课程，以详细说明我要完成的工作...我有很好的预感，这与使用“ lock”关键字有关，但我不是100 ％知道如何使用。

在您的答案中，请提供一个解决方案代码示例，以使您的答案清晰明了。谢谢！

代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
using System.Diagnostics;

namespace MyNamespace
{
    class Class1
    {
        static void Main()
        {
            Debug.WriteLine("starting application...");

            int threadcount = 2;
            List<Task> tasks = new List<Task>();

            List<Class2> myObjs = new List<Class2>();
            myObjs.Add(new Class2("list item 1"));
            myObjs.Add(new Class2("list item 2"));
            myObjs.Add(new Class2("list item 3"));
            myObjs.Add(new Class2("list item 4"));
            myObjs.Add(new Class2("list item 5"));
            myObjs.Add(new Class2("list item 6"));
            myObjs.Add(new Class2("list item 7"));
            myObjs.Add(new Class2("list item 8"));
            myObjs.Add(new Class2("list item 9"));

            Debug.WriteLine("about to create " + threadcount + " task(s)...");

            int t = 0;
            do
            {
                t++;
                Debug.WriteLine("creating task " + t);
                Class3 starter = new Class3();
                tasks.Add(starter.StartNewThread(myObjs));
            } while (t < threadcount);

            Task.WaitAll(tasks.ToArray());
            Debug.WriteLine("all tasks have completed");
        }
    }

    class Class2
    {
        private string m_status;
        public string status
        {
            get { return m_status; }
            set { m_status = value; }
        }

        private string m_text;
        public string text
        {
            get { return m_text; }
            set { m_text = value; }
        }

        private int m_threadid;
        public int threadid
        {
            get { return m_threadid; }
            set { m_threadid = value; }
        }

        public Class2()
        {
            m_status = "created";
            m_text = "";
            m_threadid = 0;
        }
        public Class2(string intext)
        {
            m_status = "created";
            m_text = intext;
            m_threadid = 0;
        }
    }

    class Class3
    {
        public Task StartNewThread(List<Class2> taskObjs)
        {
            Task<List<Class2>> task = Task.Factory
                .StartNew(() => threadTaskWorker(taskObjs),
                CancellationToken.None,
                TaskCreationOptions.None,
                TaskScheduler.Default)
                .ContinueWith(completed_task => threadTaskComplete(completed_task.Result));

            return task;
        }
        private List<Class2> threadTaskWorker(List<Class2> taskObjs)
        {
            Thread.CurrentThread.Name = "thread" + Thread.CurrentThread.ManagedThreadId;
            Debug.WriteLine("thread #" + Thread.CurrentThread.ManagedThreadId + " created.");

            //Process all items in the list that need processing
            Class2 nextObj;
            do
            {
                //Look for next item in list that needs processing
                nextObj = null;
                foreach (Class2 taskObj in taskObjs)
                {
                    if (taskObj.status == "created")
                    {
                        nextObj = taskObj;
                        break;
                    }
                }

                if (nextObj != null)
                {
                    Debug.WriteLine("thread #" + Thread.CurrentThread.ManagedThreadId +
                        " is handling " + nextObj.text);

                    nextObj.status = "processing";
                    nextObj.threadid = Thread.CurrentThread.ManagedThreadId;
                    nextObj.text += "(handled)";

                    Random rnd = new Random();
                    Thread.Sleep(rnd.Next(300, 3000));

                    nextObj.status = "completed";
                }
            } while (nextObj != null);

            Debug.WriteLine("thread #" + Thread.CurrentThread.ManagedThreadId + " destroyed.");

            //Return the task object
            return taskObjs;
        }
        private List<Class2> threadTaskComplete(List<Class2> taskObjs)
        {
            Debug.WriteLine("a thread has finished, here are the current item's status...");

            foreach (Class2 taskObj in taskObjs)
            {
                Debug.WriteLine(taskObj.text +
                    " thread:" + taskObj.threadid +
                    " status:" + taskObj.status);
            }

            //Return the task object
            return taskObjs;
        }
    }
}

结果：

/*
starting application...
about to create 2 task(s)...
creating task 1
creating task 2
thread #10 created.
thread #11 created.
thread #10 is handling list item 1
thread #11 is handling list item 1
thread #10 is handling list item 2
thread #11 is handling list item 2
thread #10 is handling list item 3
thread #11 is handling list item 4
thread #10 is handling list item 5
thread #11 is handling list item 5
thread #10 is handling list item 6
thread #11 is handling list item 6
thread #10 is handling list item 7
thread #11 is handling list item 8
thread #10 is handling list item 9
thread #11 destroyed.
a thread has finished, here are the current item's status...
list item 1(handled) thread:11 status:completed
list item 2(handled)(handled) thread:11 status:completed
list item 3(handled) thread:10 status:completed
list item 4(handled) thread:11 status:completed
list item 5(handled)(handled) thread:11 status:completed
list item 6(handled)(handled) thread:11 status:completed
list item 7(handled) thread:10 status:completed
list item 8(handled) thread:11 status:completed
list item 9(handled) thread:10 status:processing
thread #10 destroyed.
a thread has finished, here are the current item's status...
list item 1(handled) thread:11 status:completed
list item 2(handled)(handled) thread:11 status:completed
list item 3(handled) thread:10 status:completed
list item 4(handled) thread:11 status:completed
list item 5(handled)(handled) thread:11 status:completed
list item 6(handled)(handled) thread:11 status:completed
list item 7(handled) thread:10 status:completed
list item 8(handled) thread:11 status:completed
list item 9(handled) thread:10 status:completed
all tasks have completed
*/

预期结果：

/*
starting application...
about to create 2 task(s)...
creating task 1
creating task 2
thread #10 created.
thread #11 created.
thread #10 is handling list item 1
thread #11 is handling list item 2
thread #10 is handling list item 3
thread #11 is handling list item 4
thread #10 is handling list item 5
thread #10 is handling list item 6
thread #11 is handling list item 7
thread #10 is handling list item 8
thread #11 is handling list item 9
thread #10 destroyed.
a thread has finished, here are the current item's status...
list item 1(handled) thread:10 status:completed
list item 2(handled) thread:11 status:completed
list item 3(handled) thread:10 status:completed
list item 4(handled) thread:11 status:completed
list item 5(handled) thread:10 status:completed
list item 6(handled) thread:10 status:completed
list item 7(handled) thread:11 status:completed
list item 8(handled) thread:10 status:completed
list item 9(handled) thread:11 status:processing
thread #11 destroyed.
a thread has finished, here are the current item's status...
list item 1(handled) thread:10 status:completed
list item 2(handled) thread:11 status:completed
list item 3(handled) thread:10 status:completed
list item 4(handled) thread:11 status:completed
list item 5(handled) thread:10 status:completed
list item 6(handled) thread:10 status:completed
list item 7(handled) thread:11 status:completed
list item 8(handled) thread:10 status:completed
list item 9(handled) thread:11 status:completed
all tasks have completed
*/