BackgroudWorker就是一个封装好的异步处理类(就是多线程，广泛用于winform开发中)
例子：
1.界面效果：
一个label，两个button
2.Form2.cs的代码
1 using System;
2 using System.Collections.Generic;
3 using System.ComponentModel;
4 using System.Data;
5 using System.Drawing;
6 using System.Linq;
7 using System.Text;
8 using System.Windows.Forms;
9
10 namespace BackgroundWorkerTest
11 {
12 public partial class Form2 : Form
13 {
14 /*
15 * 使用BackgroundWorker的用法很多
16 * 1.可以直接从左边控件列表中拖一个到界面中
17 * 2.动态写代码生成，这里我是把它作为成员变量了
18 * **/
19 private BackgroundWorker _worker = new BackgroundWorker();
20
21 public Form2()
22 {
23 InitializeComponent();
24
25 //设置是否允许报告进度
26 _worker.WorkerReportsProgress = true;
27 //设置是否允许取消
28 _worker.WorkerSupportsCancellation = true;
29
30
31 //BackgroundWorker的三个事件之一，异步处理是所要执行的动作
32 _worker.DoWork += new DoWorkEventHandler(_worker_DoWork);
33
34 //BackgroundWorker的三个事件之二，当进度改变时所要执行的动作
35 _worker.ProgressChanged += new ProgressChangedEventHandler(_worker_ProgressChanged);
36
37 //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
38 _worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(_worker_RunWorkerCompleted);
39 }
40
41
42 //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
43 void _worker_DoWork(object sender, DoWorkEventArgs e)
44 {
45 //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
46 Person tommy = new Person("Tommy.Huang","25","CXY");
47
48 for (int i = 1; i <= 100; i++)
49 {
50 //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
51 //CancellationPending用于判断是运行了CancelAsync()方法
52 if (_worker.CancellationPending)
53 {
54 e.Cancel = true;
55 break;
56 }
57 else
58 {
59 _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
60 //因为太快，看不到效果，所以让线程每一次暂停半秒
61 System.Threading.Thread.Sleep(100);
62 }
63 }
64 }
65
66 //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
67 void _worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
68 {
69 Person p = e.UserState as Person;
70 this.label1.Text = e.ProgressPercentage.ToString()+"% -"+p.Name;
71 }
72
73 //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
74 void _worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
75 {
76 if (e.Cancelled)
77 System.Windows.Forms.MessageBox.Show("取消了");
78 else
79 System.Windows.Forms.MessageBox.Show("完成了！");
80 }
81
82 private void btnStart_Click(object sender, EventArgs e)
83 {
84 //需要先判断backgroundWorker是否正在运行
85 if (!_worker.IsBusy)
86 {
87 //RunWorkerAsync()启动线程
88 _worker.RunWorkerAsync();
89 }
90 }
91
92 private void btnCancel_Click(object sender, EventArgs e)
93 {
94 //先判断backgroundWorker是否支持取消
95 if (_worker.WorkerSupportsCancellation)
96 {
97 //CancelAsync()取消线程
98 _worker.CancelAsync();
99 }
100 }
101
102 }
103 }
3.控件代码：Form2.Designer.cs
1 namespace BackgroundWorkerTest
2 {
3 partial class Form2
4 {
5 /// <summary>
6 /// Required designer variable.
7 /// </summary>
8 private System.ComponentModel.IContainer components = null;
9
10 /// <summary>
11 /// Clean up any resources being used.
12 /// </summary>
13 /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
14 protected override void Dispose(bool disposing)
15 {
16 if (disposing && (components != null))
17 {
18 components.Dispose();
19 }
20 base.Dispose(disposing);
21 }
22
23 #region Windows Form Designer generated code
24
25 /// <summary>
26 /// Required method for Designer support - do not modify
27 /// the contents of this method with the code editor.
28 /// </summary>
29 private void InitializeComponent()
30 {
31 this.btnStart = new System.Windows.Forms.Button();
32 this.btnCancel = new System.Windows.Forms.Button();
33 this.label1 = new System.Windows.Forms.Label();
34 this.SuspendLayout();
35 //
36 // btnStart
37 //
38 this.btnStart.Location = new System.Drawing.Point(42, 165);
39 this.btnStart.Name = "btnStart";
40 this.btnStart.Size = new System.Drawing.Size(75, 23);
41 this.btnStart.TabIndex = 0;
42 this.btnStart.Text = "开始";
43 this.btnStart.UseVisualStyleBackColor = true;
44 this.btnStart.Click += new System.EventHandler(this.btnStart_Click);
45 //
46 // btnCancel
47 //
48 this.btnCancel.Location = new System.Drawing.Point(249, 165);
49 this.btnCancel.Name = "btnCancel";
50 this.btnCancel.Size = new System.Drawing.Size(75, 23);
51 this.btnCancel.TabIndex = 1;
52 this.btnCancel.Text = "取消";
53 this.btnCancel.UseVisualStyleBackColor = true;
54 this.btnCancel.Click += new System.EventHandler(this.btnCancel_Click);
55 //
56 // label1
57 //
58 this.label1.AutoSize = true;
59 this.label1.Location = new System.Drawing.Point(61, 47);
60 this.label1.Name = "label1";
61 this.label1.Size = new System.Drawing.Size(35, 13);
62 this.label1.TabIndex = 2;
63 this.label1.Text = "label1";
64 //
65 // Form2
66 //
67 this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
68 this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
69 this.ClientSize = new System.Drawing.Size(388, 230);
70 this.Controls.Add(this.label1);
71 this.Controls.Add(this.btnCancel);
72 this.Controls.Add(this.btnStart);
73 this.Name = "Form2";
74 this.Text = "Form2";
75 this.ResumeLayout(false);
76 this.PerformLayout();
77
78 }
79
80 #endregion
81
82 private System.Windows.Forms.Button btnStart;
83 private System.Windows.Forms.Button btnCancel;
84 private System.Windows.Forms.Label label1;
85 }
86 }
时间： 2024-08-02 02:52:59