详解C#中线程传参,返回值和多线程冲突问题的解决_开发_开发者

1、线程的单一参数传递

        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 = $"传入的参数：{Str}";
            }));
        }

2、线程的多参数传递以及返回值

上面的例子是单一的参数，参数要求是对象，使用的时候进行了拆箱，根据上面的例子对于多参数，可以使用中间对象来处理，就是在中间对象中放置参数和获取处理后的结果。

        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、多线程可能引起的冲突

多线程在处理同一对象时容易引起潜在的冲突，这个显而易见，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; }
                setphp { Deposit = value; }
            }
 
            public void ThreadAdd()
            {
                for (int i = 0; i < 1000000; i++)
                {
                    this.Deposit = this.Deposit + 1;
                }
            }
 
            public void ThreadReduce()
            {
                开发者_C入门for (int i = 0; i < 1000000; i++)
                {
                    this.Deposit = this.Deposit - 1;
                }
http://www.devze.com            }
        }

显示结果：

详解C#中线程传参,返回值和多线程冲突问题的解决

按道理， FI.PersonDeposit的值是123，加了1000000，也减了1000000，那么最终的结果应该还是123，为什么会是这样呢？

这就是多线程在处理同一对象时所产生的冲突了，产生的就是所谓的“脏数据”。

上面的代码因为等待线程执行完，进行了休眠，可以使用Task来写更简单。

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

Task是比Thread更加高级的概念，一个Task至少包含一个Thread。

解决上面的冲突就是对可能引起冲突的对象进行加锁判断。

完整代码：

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
 编程客栈   {
 
        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);
      javascript      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;
                    }                    
                }
            }
        }
    }
}

显示结果：

详解C#中线程传参,返回值和多线程冲突问题的解决