BackgroundWorker学习（转载）

学习了多线程BackgroundWorker，以此记录。

 此案例功能：

     实现用BackgroundWorker处理进度条，可以开始，暂停，继续，清空。

 BackgroundWorker说明：   摘抄自---http://msdn.microsoft.com

      BackgroundWorker 类允许您在单独的专用线程上运行操作。耗时的操作（如下载和数据库事务）在长时间运行时可能会导致用户界面 (UI) 似乎处于停止响应状态。如果您需要能进行响应的用户界面，而且面临与这类操作相关的长时间延迟，则可以使用 BackgroundWorker 类方便地解决问题。若要在后台执行耗时的操作，请创建一个 BackgroundWorker，侦听那些报告操作进度并在操作完成时发出信号的事件。可以通过编程方式创建 BackgroundWorker，也可以将它从“工具箱”的“组件”选项卡中拖到窗体上。如果在 Windows 窗体设计器中创建 BackgroundWorker，则它会出现在组件栏中，而且它的属性会显示在“属性”窗口中。若要设置后台操作，请为 DoWork 事件添加一个事件处理程序。在此事件处理程序中调用耗时的操作。若要启动该操作，请调用 RunWorkerAsync。若要收到进度更新通知，请对 ProgressChanged 事件进行处理。若要在操作完成时收到通知，请对 RunWorkerCompleted 事件进行处理。

     您必须非常小心，确保在 DoWork 事件处理程序中不操作任何用户界面对象。而应该通过 ProgressChanged 和 RunWorkerCompleted 事件与用户界面进行通信。

     BackgroundWorker 事件不跨 AppDomain 边界进行封送处理。请不要使用 BackgroundWorker 组件在多个 AppDomain 中执行多线程操作。如果后台操作需要参数，请在调用 RunWorkerAsync 时给出参数。在 DoWork 事件处理程序内部，可以从 DoWorkEventArgs..::.Argument 属性中提取该参数。

 

界面Code
namespace WindowsApplication1
{
    partial class Form1
    {
        /**//// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /**//// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        Windows Form Designer generated code#region Windows Form Designer generated code

        /**//// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.colorDialog1 = new System.Windows.Forms.ColorDialog();
            this.colorDialog2 = new System.Windows.Forms.ColorDialog();
            this.progressBar1 = new System.Windows.Forms.ProgressBar();
            this.button1 = new System.Windows.Forms.Button();
            this.button2 = new System.Windows.Forms.Button();
            this.button3 = new System.Windows.Forms.Button();
            this.textBox2 = new System.Windows.Forms.TextBox();
            this.backgroundWorker1 = new System.ComponentModel.BackgroundWorker();
            this.label3 = new System.Windows.Forms.Label();
            this.label1 = new System.Windows.Forms.Label();
            this.button4 = new System.Windows.Forms.Button();
            this.SuspendLayout();
            // 
            // progressBar1
            // 
            this.progressBar1.Location = new System.Drawing.Point(27, 85);
            this.progressBar1.Name = "progressBar1";
            this.progressBar1.Size = new System.Drawing.Size(218, 23);
            this.progressBar1.TabIndex = 0;
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(12, 222);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(54, 23);
            this.button1.TabIndex = 1;
            this.button1.Text = "Execute ";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // button2
            // 
            this.button2.Location = new System.Drawing.Point(72, 222);
            this.button2.Name = "button2";
            this.button2.Size = new System.Drawing.Size(53, 23);
            this.button2.TabIndex = 2;
            this.button2.Text = "Cancel";
            this.button2.UseVisualStyleBackColor = true;
            this.button2.Click += new System.EventHandler(this.button2_Click);
            // 
            // button3
            // 
            this.button3.Location = new System.Drawing.Point(131, 222);
            this.button3.Name = "button3";
            this.button3.Size = new System.Drawing.Size(57, 23);
            this.button3.TabIndex = 3;
            this.button3.Text = "Continue ";
            this.button3.UseVisualStyleBackColor = true;
            this.button3.Click += new System.EventHandler(this.button3_Click);
            // 
            // textBox2
            // 
            this.textBox2.Location = new System.Drawing.Point(145, 124);
            this.textBox2.Name = "textBox2";
            this.textBox2.Size = new System.Drawing.Size(100, 20);
            this.textBox2.TabIndex = 5;
            // 
            // backgroundWorker1
            // 
            this.backgroundWorker1.WorkerReportsProgress = true;
            this.backgroundWorker1.WorkerSupportsCancellation = true;
            this.backgroundWorker1.DoWork += new System.ComponentModel.DoWorkEventHandler(this.backgroundWorker1_DoWork);
            this.backgroundWorker1.RunWorkerCompleted += new System.ComponentModel.RunWorkerCompletedEventHandler(this.backgroundWorker1_RunWorkerCompleted);
            this.backgroundWorker1.ProgressChanged += new System.ComponentModel.ProgressChangedEventHandler(this.backgroundWorker1_ProgressChanged);
            // 
            // label3
            // 
            this.label3.AutoSize = true;
            this.label3.Location = new System.Drawing.Point(33, 175);
            this.label3.Name = "label3";
            this.label3.Size = new System.Drawing.Size(54, 13);
            this.label3.TabIndex = 6;
            this.label3.Text = "UserState";
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(24, 127);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(109, 13);
            this.label1.TabIndex = 7;
            this.label1.Text = "Please input  number:";
            // 
            // button4
            // 
            this.button4.Location = new System.Drawing.Point(194, 222);
            this.button4.Name = "button4";
            this.button4.Size = new System.Drawing.Size(61, 23);
            this.button4.TabIndex = 8;
            this.button4.Text = "Clear";
            this.button4.UseVisualStyleBackColor = true;
            this.button4.Click += new System.EventHandler(this.button4_Click);
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(292, 273);
            this.Controls.Add(this.button4);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.label3);
            this.Controls.Add(this.textBox2);
            this.Controls.Add(this.button3);
            this.Controls.Add(this.button2);
            this.Controls.Add(this.button1);
            this.Controls.Add(this.progressBar1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.ColorDialog colorDialog1;
        private System.Windows.Forms.ColorDialog colorDialog2;
        private System.Windows.Forms.ProgressBar progressBar1;
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Button button2;
        private System.Windows.Forms.Button button3;
        private System.Windows.Forms.TextBox textBox2;
        private System.ComponentModel.BackgroundWorker backgroundWorker1;
        private System.Windows.Forms.Label label3;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Button button4;
    }
}

 

 

Code
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Threading;
using System.Net;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        //加载窗体
        public Form1()
        {
            InitializeComponent();
        }
        define#region define
        int i = 0;
        int j = 0;
        bool f = false;
        #endregion
      
        private void button1_Click(object sender, EventArgs e)
        {
            backgroundWorker1.RunWorkerAsync();

        }
        //按钮单击事件启动后台线程DoWok事件
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker worker = (BackgroundWorker)sender;
            int num = int.Parse(textBox2.Text);
            if (f == false)
            {
                for (i = 0; i < num; i++)
                {
                    if (!worker.CancellationPending)
                    {
                        j = i;
                        Thread.Sleep(100);
                        worker.ReportProgress(i * 100 / num, i);
                        if (backgroundWorker1.CancellationPending)
                        {

                            e.Cancel = true;

                            break;
                        }

                    }
                }
            }
            else
            {
                for (i = j; i < num; i++)
                {
                    if (!worker.CancellationPending)
                    {
                        j = i;
                        Thread.Sleep(100);
                        worker.ReportProgress(i * 100 / num, i);
                        if (backgroundWorker1.CancellationPending)
                        {

                            e.Cancel = true;

                            break;
                        }

                    }

                }
            }
            
        }

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            progressBar1.Value = e.ProgressPercentage;
            label3.Text = e.UserState.ToString();
        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled)
            {
                label3.Text = "已经取消！";
            }

            else
            {
                MessageBox.Show("ok");
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            backgroundWorker1.CancelAsync();
           
            label3.Text = "正在取消。。";
        }

        private void button3_Click(object sender, EventArgs e)
        {
            f = true;
            backgroundWorker1.RunWorkerAsync();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            backgroundWorker1.CancelAsync();
         
            this.progressBar1.Value = 0;
            f = false;
            this.label3.Text = "";
            this.textBox2.Text = "";
            
        }


    }
}