C#中Backgroundworker与Thread的区别

目录

最近项目要用到，窗体Form程序要在后台开启几个子线程，负责和其他端进行通信，异步读写，并且来更改UI。在网上查了有Backgroundworker与Thread两种方法。

1.Backgroundworker

BackgroundWorker是微软的在.net>

首先介绍一下BackgroundWorker的相关属性和方法：

属性：

WorkerReportsProgress：是否可以报告进度。WorkerSupportsCancellation：是否允许异步中止。IsBusy：是否在运行。CancellationPending：判断BackgroundWorker是否已经异步取消。

方法：

RunWorkerAsync：开始执行任务。触发DoWork事件ReportProgress：异步提醒，触发ProgressChanged事件，但是这个如果可以使用，必须设置WorkerReportsProgress为TrueCancelAsync：取消BackgroundWorker操作。

事件：

DoWork：执行RunWorkerAsync后触发，异步执行的认为。ProgressChanged：执行ReportProgress时触发，异步获得进度。RunWorkerCompleted：线程结束时触发，主要有成功结束，发生异常或者取消时发生。

一个简单的例子：

public partial class MainWindow : Window
    {
 
        private BackgroundWorker m_BackgroundWorker;// 申明后台对象
 
        public MainWindow()
        {
            InitializeComponent();
 
            m_BackgroundWorker = new BackgroundWorker(); // 实例化后台对象
 
            m_BackgroundWorker.WorkerReportsProgress = true; // 设置可以通告进度
            m_BackgroundWorker.WorkerSupportsCancellation = true; // 设置可以取消
 
            m_BackgroundWorker.DoWork += new DoWorkEventHandler(DoWork);
            m_BackgroundWorker.ProgressChanged += new ProgressChangedEventHandler(UpdateProgress);
            m_BackgroundWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(CompletedWork);
 
            m_BackgroundWorker.RunWorkerAsync(this);
        }
 
 
        void DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker bw = sender as BackgroundWorker;
            MainWindow win = e.Argument as MainWindow;
 
            int i = 0;
            while ( i <= 100 )
            {
                if (bw.CancellationPending)
                {
                    e.Cancel = true;
                    break;
                }
 
                bw.ReportProgress(i++);
     
                Thread.Sleep(1000);
 
            }
        }
 
        void UpdateProgress(object sender, ProgressChangedEventArgs e)
        {
            int progress = e.ProgressPercentage;
 
            label1.Content = string.Format("{0}",progress);
        }
 
 
        void CompletedWork(object sender, RunWorkerCompletedEventArgs e)
        {
            if ( e.Error != null)
            {
                MessageBox.Show("Error");
            }
            else if (e.Cancelled)
            {
                MessageBox.Show("Canceled");
            }
            else
            {
                MessageBox.Show("Completed");
            }
        }
 
 
        private void button1_Click(object sender, RoutedEventArgs e)
        {
            m_BackgroundWorker.CancelAsync();
        }
    }  

2.Thread

BackgroundWorker就是一个高级控件,方便使用Thread,后者是前者的灵魂或基础
直接使用后者难度稍大,但换来的是灵活方便。

Thread的使用就比较麻烦了，对于尤其是对异步提醒来说，需要写委托，代码量是很多，但是对于BackgroundWorker来说，却没有线程暂停和继续的方法。但是对于一般的来说，这些功能也是不用的，而且在微软的文档中还提到了，Thread的Resume和Suspend已经不推荐使用。

一个简单的例子：

using System;
using System.Threading;
 
namespace ThreadsComm
{
    public delegate void ReadParamEventHandler(string sParam);
    class MyThread
    {
        public Thread thread1;
        private static ReadParamEventHandler OnReadParamEvent;
        public MyThread()
        {
            thread1 = new Thread(new ThreadStart(MyRead));
            thread1.IsBackground = true;
            thread1.Start();
        }
        public event ReadParamEventHandler ReadParam
        {
            add { OnReadParamEvent += new ReadParamEventHandler(value);}
            remove{ OnReadParamEvent -= new ReadParamEventHandler(value);}
        }
        protected void MyRead()
        {
            int i = 0;
            while (true)
            {
                Thread.Sleep(1000);
                i = i + 1;
                OnReadParamEvent(i.ToString());//触发事件
            }
        }
    }
}
using System;
using System.Windows.Forms;
 
namespace ThreadsComm
{
    public partial class Form1 : Form
    {
        private static string param = "";
        public Form1()
        {
            InitializeComponent();
            MyThread thread1 = new MyThread();
            thread1.ReadParam += this.OnRead;
        }
 
        private void OnRead(string sParam)
        {
            param = sParam;
            Object[] list = { this,System.EventArgs.Empty};
            this.lblShow.BeginInvoke(new EventHandler(LabelShow), list);
        }
        protected void LabelShow(Object o, EventArgs e)
        {
            this.lblShow.Text = param;
        }
    }
}

3.总结

当你执行的任务较简单,不需要复杂控制时使用BackgroundWorker,较为方便;当你要执行的任务需要复杂控制(如线程同步)时,要自己>

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