thread学习笔记--BackgroundWorker 类

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApp_BackGroundWorker
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            //设置能够报告进度更新
            //设置能够支持异步取消
            backgroundWorker1.WorkerReportsProgress = true;
            backgroundWorker1.WorkerSupportsCancellation = true;
        }

             //在designer里的属性设计器里直接双击就添加了对backgroundWorker1的ProgressChanged的事件处理程序
            //this.backgroundWorker1.DoWork += new System.ComponentModel.DoWorkEventHandler(this.backgroundWorker1_DoWork);
            //this.backgroundWorker1.ProgressChanged += new System.ComponentModel.ProgressChangedEventHandler(this.backgroundWorker1_ProgressChanged);
            //this.backgroundWorker1.RunWorkerCompleted += new System.ComponentModel.RunWorkerCompletedEventHandler(this.backgroundWorker1_RunWorkerCompleted);


        //由ReportProgress方法触发，通过响应消息，来处理界面的显示工作
        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            //获取异步操作进度百分比，主线程
            this.progressBar1.Value = e.ProgressPercentage;
            this.label1.Text = e.UserState.ToString();
            this.label1.Update();

        }


        //后台工作完成时引发的事件，可以在此事件处理程序里面写进行后续的处理工作，比如提示
        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            //MessageBox.Show("计算终于完成了！");
            if (!e.Cancelled && e.Error == null)
            {
                MessageBox.Show("处理完成了！" + e.Result);
            }
            else
            {
                MessageBox.Show("后台线程被取消或发生异常！");
            }
        }


        //此事件由开始按钮里的调用RunWorkerAsync方法引发
        //这里就是后台进程开始的地方，调用工作函数的地方，也可以把现有的处理函数写在这里
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
           // Countwork(this.backgroundWorker1);
            Countwork(backgroundWorker1);
        }

        //后台处理函数，真正的处理工作
        private bool Countwork(BackgroundWorker bw)
        {
            int n = 10000;
            for (int i = 0; i <= n; i++)
            {
                //判断用户是否执行了取消后台操作，是的话显示返回
                if (bw.CancellationPending)
                {
                    bw.ReportProgress(i,string.Format("当前操作值是{0}，操作被用户申请中断",i));
                    return false;
 
                }
                //ReportProgress函数的作用是，向主线程报告处理进度。折算成百分比，或者把进度条的最大值设置为10000
                bw.ReportProgress(i,string.Format("当前值是{0}",i));
            }
            return true;
 
        }

        private void button_Start_Click(object sender, EventArgs e)
        {
            //判断是否在进行异步操作，应对用户多次点击开始按钮
            if(this.backgroundWorker1.IsBusy)
            {
                return;
            }

            //触发DOWORK事件，实际就是让后台工作开始
            this.backgroundWorker1.RunWorkerAsync();
        }

        //不太好用...
        private void button_Cancel_Click(object sender, EventArgs e)
        {
            this.backgroundWorker1.CancelAsync();
            this.backgroundWorker1.Dispose();//释放资源
        }

        private void button_Exit_Click(object sender, EventArgs e)
        {
            this.Close();
        }




    }
}