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詳解C#中線程傳參,返回值和多線程沖突問(wèn)題的解決

更新時(shí)間：2022年11月30日 08:19:37 作者：dawn

這篇文章主要為大家詳細(xì)介紹了C#中線程傳參,返回值和多線程沖突問(wèn)題的解決方法，文中的示例代碼講解詳細(xì)，感興趣的小伙伴可以跟隨小編一起學(xué)習(xí)一下

1、線程的單一參數(shù)傳遞

        private void button1_Click(object sender, EventArgs e)
        {
            Thread Th1= new Thread(func);
            Th1.Start("CSDN");
            Thread.Sleep(500);
        }
 
        private void func(object Obj)
        {
            string Str = Obj as string;
            textBox1.BeginInvoke(new Action(() =>
            {
                textBox1.Text = $"傳入的參數(shù)：{Str}";
            }));
        }

2、線程的多參數(shù)傳遞以及返回值

上面的例子是單一的參數(shù)，參數(shù)要求是對(duì)象，使用的時(shí)候進(jìn)行了拆箱，根據(jù)上面的例子對(duì)于多參數(shù)，可以使用中間對(duì)象來(lái)處理，就是在中間對(duì)象中放置參數(shù)和獲取處理后的結(jié)果。

        private void button1_Click(object sender, EventArgs e)
        {
            FinancialInfo FI=new FinancialInfo();
            FI.PersonName = "CSDN";
            FI.PersonDeposit = 123;
            Thread Th1 = new Thread(FI.ThreadChangeFinanceialInfo);
            Th1.Start();
            Thread.Sleep(500);
            textBox1.Text=FI.PersonName+Environment.NewLine+FI.PersonDeposit.ToString();
        }
 
        private class FinancialInfo
        {
            private string Name=string.Empty;
            private int Deposit=0;
            public string PersonName
            {
                get { return Name; }
                set { Name = value; }
            }
 
            public int PersonDeposit
            {
                get { return Deposit; }
                set { Deposit = value; }
            }
 
            public void ThreadChangeFinanceialInfo() 
            {
                this.Name = this.Name + " | C#";
                this.Deposit = this.Deposit + 100;
            }

3、多線程可能引起的沖突

多線程在處理同一對(duì)象時(shí)容易引起潛在的沖突，這個(gè)顯而易見(jiàn)，例如：

        private void button1_Click(object sender, EventArgs e)
        {
            FinancialInfo FI = new FinancialInfo();
            FI.PersonName = "CSDN";
            FI.PersonDeposit = 123;
            Thread Th1 = new Thread(FI.ThreadAdd);
            Thread Th2 = new Thread(FI.ThreadReduce);
            Th1.Start();
            Th2.Start();
            Thread.Sleep(5000);
            textBox1.Text = textBox1.Text + FI.PersonName +"|"+FI.PersonDeposit.ToString()+Environment.NewLine;
        }
 
        private class FinancialInfo
        {
            private string Name=string.Empty;
            private int Deposit=0;
            public string PersonName
            {
                get { return Name; }
                set { Name = value; }
            }
 
            public int PersonDeposit
            {
                get { return Deposit; }
                set { Deposit = value; }
            }
 
            public void ThreadAdd()
            {
                for (int i = 0; i < 1000000; i++)
                {
                    this.Deposit = this.Deposit + 1;
                }
            }
 
            public void ThreadReduce()
            {
                for (int i = 0; i < 1000000; i++)
                {
                    this.Deposit = this.Deposit - 1;
                }
            }
        }

顯示結(jié)果：

按道理， FI.PersonDeposit的值是123，加了1000000，也減了1000000，那么最終的結(jié)果應(yīng)該還是123，為什么會(huì)是這樣呢？

這就是多線程在處理同一對(duì)象時(shí)所產(chǎn)生的沖突了，產(chǎn)生的就是所謂的“臟數(shù)據(jù)”。

上面的代碼因?yàn)榈却€程執(zhí)行完，進(jìn)行了休眠，可以使用Task來(lái)寫更簡(jiǎn)單。

            var task1 = new Task(FI.ThreadAdd);
            var task2 = new Task(FI.ThreadReduce);
            task1.Start();
            task2.Start();
 
            Task.WaitAll(task1,task2);

Task是比Thread更加高級(jí)的概念，一個(gè)Task至少包含一個(gè)Thread。

解決上面的沖突就是對(duì)可能引起沖突的對(duì)象進(jìn)行加鎖判斷。

完整代碼：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Text;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
 
namespace MultiThread
{
    public partial class Form3 : Form
    {
 
        private static readonly object LockObj=new object();
 
        public Form3()
        {
            InitializeComponent();
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            FinancialInfo FI = new FinancialInfo();
            FI.PersonName = "CSDN";
            FI.PersonDeposit = 123;
            var task1 = new Task(FI.ThreadAdd);
            var task2 = new Task(FI.ThreadReduce);
            task1.Start();
            task2.Start();
            Task.WaitAll(task1, task2);
            textBox1.Text = textBox1.Text + FI.PersonName +"|"+FI.PersonDeposit.ToString()+Environment.NewLine;
        }
 
 
        private class FinancialInfo
        {
            private string Name=string.Empty;
            private int Deposit=0;
            public string PersonName
            {
                get { return Name; }
                set { Name = value; }
            }
 
            public int PersonDeposit
            {
                get { return Deposit; }
                set { Deposit = value; }
            }
 
            public void ThreadChangeFinanceialInfo() 
            {
                this.Name = this.Name + " | C#";
                this.Deposit = this.Deposit + 100;
            }
 
            public void ThreadAdd()
            {
                for (int i = 0; i < 1000000; i++)
                {
                    lock(LockObj)
                    {
                        this.Deposit = this.Deposit + 1;
                    }                    
                }
            }
 
            public void ThreadReduce()
            {
                for (int i = 0; i < 1000000; i++)
                {
                    lock(LockObj)
                    {
                        this.Deposit = this.Deposit - 1;
                    }                    
                }
            }
        }
    }
}

顯示結(jié)果：