BackgroundWorker的简单用法

 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 BackgroundWorkerTest

 {

     public partial class Form2 : Form

     {

         /*

          * 使用BackgroundWorker的用法很多

          * 1.可以直接从左边控件列表中拖一个到界面中

          * 2.动态写代码生成，这里我是把它作为成员变量了

          * **/

         private BackgroundWorker _worker = new BackgroundWorker();

         public Form2()

         {

             InitializeComponent();

             //设置是否允许报告进度

             _worker.WorkerReportsProgress = true;

             //设置是否允许取消

             _worker.WorkerSupportsCancellation = true;

             //BackgroundWorker的三个事件之一，异步处理是所要执行的动作

             _worker.DoWork += new DoWorkEventHandler(_worker_DoWork);

             //BackgroundWorker的三个事件之二，当进度改变时所要执行的动作

             _worker.ProgressChanged += new ProgressChangedEventHandler(_worker_ProgressChanged);

             //BackgroundWorker的三个事件之三，当任务正常完成或手动取消时，所要执行的动作

             _worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(_worker_RunWorkerCompleted);

         }

         //运行RunWorkerAsync()时就出发此方法，而且此方法不能与UI有交互，会抛异常

         void _worker_DoWork(object sender, DoWorkEventArgs e)

         {

             //这个类是用来测试报告进度时，除了可以报告进度外，还可以返回一个object的变量

             Person tommy = new Person("Tommy.Huang","","CXY");

             for (int i = ; i <= ; i++)

             {

                 //如果想要实现能够中途取消的功能，就必须在DoWork里面判断是否点击了取消

                 //CancellationPending用于判断是运行了CancelAsync()方法

                 if (_worker.CancellationPending)

                 {

                     e.Cancel = true;

                     break;

                 }

                 else

                 {

                     _worker.ReportProgress(i,tommy);//ReportProgress可以带1个或2个参数，第一个为进度int，第二个为object

                     //因为太快，看不到效果，所以让线程每一次暂停半秒

                     System.Threading.Thread.Sleep();

                 }

             }

         }

         //当进度有所改变时，就会触发该方法，此方法可以与UI交互，所以通常在此方法中处理

         void _worker_ProgressChanged(object sender, ProgressChangedEventArgs e)

         {

             Person p = e.UserState as Person;

             this.label1.Text = e.ProgressPercentage.ToString()+"% -"+p.Name;

         }

         //当异步线程正常运行结束，或者点击取消时都会执行此方法

         void _worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)

         {

             if (e.Cancelled)

                 System.Windows.Forms.MessageBox.Show("取消了");

             else

                 System.Windows.Forms.MessageBox.Show("完成了！");

         }

         private void btnStart_Click(object sender, EventArgs e)

         {

             //需要先判断backgroundWorker是否正在运行

             if (!_worker.IsBusy)

             {

                 //RunWorkerAsync()启动线程

                 _worker.RunWorkerAsync();

             }

         }

         private void btnCancel_Click(object sender, EventArgs e)

         {

             //先判断backgroundWorker是否支持取消

             if (_worker.WorkerSupportsCancellation)

             {

                 //CancelAsync()取消线程

                 _worker.CancelAsync();

             }

         }

     }

 }

 namespace BackgroundWorkerTest

 {

     partial class Form2

     {

         /// <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.btnStart = new System.Windows.Forms.Button();

             this.btnCancel = new System.Windows.Forms.Button();

             this.label1 = new System.Windows.Forms.Label();

             this.SuspendLayout();

             //

             // btnStart

             //

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

             this.btnStart.Name = "btnStart";

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

             this.btnStart.TabIndex = ;

             this.btnStart.Text = "开始";

             this.btnStart.UseVisualStyleBackColor = true;

             this.btnStart.Click += new System.EventHandler(this.btnStart_Click);

             //

             // btnCancel

             //

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

             this.btnCancel.Name = "btnCancel";

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

             this.btnCancel.TabIndex = ;

             this.btnCancel.Text = "取消";

             this.btnCancel.UseVisualStyleBackColor = true;

             this.btnCancel.Click += new System.EventHandler(this.btnCancel_Click);

             //

             // 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 = "label1";

             //

             // Form2

             //

             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.label1);

             this.Controls.Add(this.btnCancel);

             this.Controls.Add(this.btnStart);

             this.Name = "Form2";

             this.Text = "Form2";

             this.ResumeLayout(false);

             this.PerformLayout();

         }

         #endregion

         private System.Windows.Forms.Button btnStart;

         private System.Windows.Forms.Button btnCancel;

         private System.Windows.Forms.Label label1;

     }

 }