多线程BackgroundWorker

链接：http://www.cnblogs.com/yiyisawa/archive/2008/11/24/1339826.html

周六闲来无事，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。

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);

        }

        #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(, );

            this.progressBar1.Name = "progressBar1";

            this.progressBar1.Size = new System.Drawing.Size(, );

            this.progressBar1.TabIndex = ;

            // 

            // button1

            // 

            this.button1.Location = new System.Drawing.Point(, );

            this.button1.Name = "button1";

            this.button1.Size = new System.Drawing.Size(, );

            this.button1.TabIndex = ;

            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(, );

            this.button2.Name = "button2";

            this.button2.Size = new System.Drawing.Size(, );

            this.button2.TabIndex = ;

            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(, );

            this.button3.Name = "button3";

            this.button3.Size = new System.Drawing.Size(, );

            this.button3.TabIndex = ;

            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(, );

            this.textBox2.Name = "textBox2";

            this.textBox2.Size = new System.Drawing.Size(, );

            this.textBox2.TabIndex = ;

            // 

            // 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(, );

            this.label3.Name = "label3";

            this.label3.Size = new System.Drawing.Size(, );

            this.label3.TabIndex = ;

            this.label3.Text = "UserState";

            // 

            // label1

            // 

            this.label1.AutoSize = true;

            this.label1.Location = new System.Drawing.Point(, );

            this.label1.Name = "label1";

            this.label1.Size = new System.Drawing.Size(, );

            this.label1.TabIndex = ;

            this.label1.Text = "Please input  number:";

            // 

            // button4

            // 

            this.button4.Location = new System.Drawing.Point(, );

            this.button4.Name = "button4";

            this.button4.Size = new System.Drawing.Size(, );

            this.button4.TabIndex = ;

            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(, );

            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;

    }

}

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();

        }

        #region define

        int i = ;

        int j = ;

        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 = ; i < num; i++)

                {

                    if (!worker.CancellationPending)

                    {

                        j = i;

                        Thread.Sleep();

                        worker.ReportProgress(i *  / num, i);

                        if (backgroundWorker1.CancellationPending)

                        {

                            e.Cancel = true;

                            break;

                        }

                    }

                }

            }

            else

            {

                for (i = j; i < num; i++)

                {

                    if (!worker.CancellationPending)

                    {

                        j = i;

                        Thread.Sleep();

                        worker.ReportProgress(i *  / 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 = ;

            f = false;

            this.label3.Text = "";

            this.textBox2.Text = "";

            

        }

    }

}