如何在C＃中將鍵值對並行添加到字典中

Question

這是我的代碼：

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

namespace ConsoleApplication2
{
    public class c_Thread
    {
        public bool ThreadOngoing;

        public c_Thread()
        {
            ThreadOngoing = false;
        }

        public void CallToChildThread(string key, ref List<int> nums,
                ref Dictionary<string, List<int>> container)
        {
            container.Add(key, nums);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            c_Thread cc = new c_Thread();

            Dictionary<string, List<int>> container1 = new Dictionary<string, List<int>>();

            List<int> aList = new List<int>();
            List<int> bList = new List<int>();

            string printLine;

            aList.Add(2);
            aList.Add(4);
            aList.Add(2);
            bList.Add(1);
            bList.Add(3);
            bList.Add(1);

            Thread myNewThread1 = new Thread(() => 
                cc.CallToChildThread("param1", ref aList, ref container1));
            myNewThread1.Start();

            Thread myNewThread2 = new Thread(() =>
                cc.CallToChildThread("param2", ref bList, ref container1));
            myNewThread2.Start();

            while (myNewThread1.ThreadState == ThreadState.Running &&
                   myNewThread2.ThreadState == ThreadState.Running) 
            { }

            foreach (string key in container1.Keys)
            {
                printLine = key + ": ";

                foreach(int val in container1[key])
                        printLine += val + " ";

                Console.WriteLine(printLine);
            }

            Console.ReadKey();
        }
    }
}

我正在嘗試將項目並行添加到字典中，但是打印出以下內容：

理想情況下，我想處理具有多列的txt文件，並且想將所有內容輸入到字典中，但是這需要很多時間。

param1: 2 4 2

第二個沒有打印出來，我該如何糾正？

Answer 1

問題是字典不是線程安全的。 您要使用ConcurrentDictionary。

public class c_Thread
    {
        public bool ThreadOngoing;

        public c_Thread()
        {
            ThreadOngoing = false;
        }

        public void CallToChildThread(string key, ref List<int> nums, ConcurrentDictionary<string, List<int>> container)
        {
            container.TryAdd(key, nums);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            var cc = new c_Thread();
            var container1 = new ConcurrentDictionary<string, List<int>>();
            var aList = new List<int>();
            var bList = new List<int>();
            string printLine;
            aList.Add(2);
            aList.Add(4);
            aList.Add(2);
            bList.Add(1);
            bList.Add(3);
            bList.Add(1);
            var myNewThread1 = new Thread(() => cc.CallToChildThread("param1", ref aList, container1));
            myNewThread1.Start();
            var myNewThread2 = new Thread(() => cc.CallToChildThread("param2", ref bList, container1));
            myNewThread2.Start();
            while (myNewThread1.ThreadState == ThreadState.Running && myNewThread2.ThreadState == ThreadState.Running) { }

            foreach (var key in container1.Keys)
            {
                printLine = key + ": ";
                foreach (var val in container1[key]) printLine += val + " ";
                Console.WriteLine(printLine);
            }
            Console.ReadKey();
        }
    }

Answer 2

請看看Parallel.ForEach

理想情況下，您應該使用ConcurrentDictionary 。