【C#控件专题二】BackGroundWorker控件使用

本文主要是介绍【C#控件专题二】BackGroundWorker控件使用，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

BackGroundWorker实际上是一个异步的事件进度控制控件，通常结合进度条ProgressBar一起使用，如下测试源码

using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;namespace BackGroundWorker
{public partial class BgWorkerForm : System.Windows.Forms.Form{public BgWorkerForm(){InitializeComponent();//指示BackgroundWorker是否可以报告进度更新。为True时，将可以成功调用ReportProgress方法，否则将引发InvalidOperationException异常。bgWorker.WorkerReportsProgress = true;//指示BackgroundWorker是否支持异步取消操作。为True时，将可以成功调用CancelAsync方法，否则将引发InvalidOperationException异常。bgWorker.WorkerSupportsCancellation = true; bgWorker.DoWork += BgWorker_DoWork; //执行异步操作的函数,在另一个线程中执行bgWorker.ProgressChanged += BgWorker_ProgressChanged;   //报告进度更新的函数bgWorker.RunWorkerCompleted += BgWorker_RunWorkerCompleted; //报告进度完成的函数string uiID =  Thread.CurrentThread.ManagedThreadId.ToString(); //或AppDomain.GetCurrentThreadId().ToString()mainUiLabel.Text = string.Format("主UI线程ID为:{0}", uiID);}private void BgWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e){if (e.Error != null){MessageBox.Show(e.Error.ToString());return;}if (!e.Cancelled)                       //判断是否人为终止infoLabel.Text = "处理完毕!";elseinfoLabel.Text = "处理终止!";string RunWorkerCompletedID = Thread.CurrentThread.ManagedThreadId.ToString(); //或AppDomain.GetCurrentThreadId().ToString()runWorkerCompletedLabel.Text = string.Format("RunWorkerCompleted运行线程ID为:{0}", RunWorkerCompletedID);doWorkLabel.Text = string.Format("DoWork运行线程ID为:{0}", DoWorkID);}private void BgWorker_ProgressChanged(object sender, ProgressChangedEventArgs e){progressBar.Value = e.ProgressPercentage;   //获取报告值// Extract the argument.string param = (string)e.UserState; //Working...infoLabel.Text = "处理进度:" + Convert.ToString(e.ProgressPercentage) + "%";string ProgressChangedID = Thread.CurrentThread.ManagedThreadId.ToString(); //或AppDomain.GetCurrentThreadId().ToString()progressChangedLabel.Text = string.Format("ProgressChanged运行线程ID为:{0}", ProgressChangedID);}private string DoWorkID;private void BgWorker_DoWork(object sender, DoWorkEventArgs e){// Do not access the form's BackgroundWorker reference directly.// Instead, use the reference provided by the sender parameter.BackgroundWorker bw = sender as BackgroundWorker;// Extract the argument.string param = (string)e.Argument; //param// If the operation was canceled by the user, // set the DoWorkEventArgs.Cancel property to true.//在DoWork中键入如下代码for (int i = 0; i <= 100; i++){if (bw.CancellationPending)   //状态，可检索是否取消了{//Cancel事件发生后仍会先进这里，这个函数完结了才会调用BgWorker_RunWorkerCompleted//这里的标志位决定了后续BgWorker_RunWorkerCompleted里的标志位e.Cancel = true;        return;}else{bw.ReportProgress(i, "Working...");  //提交状态报告，将触发BgWorker_ProgressChanged事件System.Threading.Thread.Sleep(100);}}DoWorkID = Thread.CurrentThread.ManagedThreadId.ToString(); //或AppDomain.GetCurrentThreadId().ToString()}private void startBtn_Click(object sender, EventArgs e){if (bgWorker.IsBusy)return; //避免还处在工作状态时被重复触发progressBar.Maximum = 100;bgWorker.RunWorkerAsync("param");}private void cancelBtn_Click(object sender, EventArgs e){bgWorker.CancelAsync(); //停止运行}private void Form_Load(object sender, EventArgs e){}}
}

运行效果：