C#运用BackgroundWorker控件实现多线程
作者:互联网
可见BackGroundWorker
有三个事件,事件间通过EventArgs
实现参数传递。有用到CancellationPending
属性判断取消。EvnentArgs
有很多属性:Cancel
、Argument
、Result
、ProgressPercentage
、UserState
属性等。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace BackGroundWorkDemo
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
this.backgroundWorker1.WorkerReportsProgress = true; // 这两个属性也可以去控件的属性栏里面改
this.backgroundWorker1.WorkerSupportsCancellation = true;
this.StartPosition = FormStartPosition.CenterScreen;
}
// Backgroundworker的三个事件
// [1]开始后台要执行的任务,可见参数都是通过 EventArgs 参数传递的。
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker bgw = sender as BackgroundWorker;
int result = 0;
for (int i = 1; i <= 100; i++) {
if (bgw.CancellationPending) {// 如果取消操作
e.Cancel = true; // 把取消结果传出去,传给 RunWorkerComplete事件中。
return;
}
result += i;// 累加
bgw.ReportProgress(i, "已经完成了" + i.ToString() + "%"); // 报告进度,第二个参数是: UserState。传给 ProgressChanged 事件。
System.Threading.Thread.Sleep((int)e.Argument);//根据外部传入参数休眠,模拟计算耗时。
e.Result = result; // 把计算结果传出去
}
}
// [2]/汇报后台工作进展
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
this.progressBar1.Value = e.ProgressPercentage;// 显示百分比
this.lblProgressPercent.Text = e.UserState.ToString();// 显示进度条上面的百分信息
}
// [3]后台任务完成
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Cancelled) {
toolStripStatusLabel1.Text = "用户取消操作";
btnBegin.Enabled = false;
return;
}
if (e.Error != null) {
toolStripStatusLabel1.Text = e.Error.Message;
return;
}
this.lblResult.Text = e.Result.ToString(); // 显示结果
this.btnBegin.Enabled = true;
toolStripStatusLabel1.Text = "计算完成";
}
// 开启任务
private void btnBegin_Click(object sender, EventArgs e)
{
lblResult.Text = "???";
lblResult.Refresh();
// 启动后台程序(参数argument传给休眠时间)
backgroundWorker1.RunWorkerAsync(20);
btnBegin.Enabled = false;
toolStripStatusLabel1.Text = "稍等,正在计算…";
}
// 取消
private void btnCancel_Click(object sender, EventArgs e)
{
backgroundWorker1.CancelAsync();
}
// 关闭
private void btnClose_Click(object sender, EventArgs e)
{
this.Close();
}
}
}
运行效果:
标签:控件,C#,System,BackgroundWorker,using,backgroundWorker1,多线程,属性 来源: https://www.cnblogs.com/huvjie/p/15336379.html