BackgroundWorker使用介绍

c#

BackgroundWorker使用介绍

用途：在单独的线程上执行任务，即在一个线程中执行一个fuction或者代码

使用

//创建BackgroundWorker对象
BackgroundWorker backgroundWorker = new BackgroundWorker();
backgroundWorker.WorkerSupportsCancellation = true; //是否支持运行时取消操作
backgroundWorker.WorkerReportsProgress = true; //是否支持 报告执行进度

//注册事件
backgroundWorker.DoWork += backgroundWorker_DoWork; //开始执行任务事件，任务运行在线程中，不可在此线程中直接更新UI线程（如设置TextBox1.Text="123"）
backgroundWorker.ProgressChanged += BackgroundWorker_ProgressChanged; //报告执行进度事件，运行在UI线程，可直接更新UI，如设置TextBox1.Text="123",ProcessBar1.Value = value
backgroundWorker.RunWorkerCompleted += BackgroundWorker_RunWorkerCompleted;//任务执行完成事件，运行在UI线程，可直接更新UI，如设置TextBox1.Text="123", ProcessBar1.Value=100

//触发任务
private void btnRun_Click(object sender, EventArgs e)
{
	string input_param = "file path";
	// 向后台任务传参
	if (backgroundWorker.IsBusy != true)
	{
		backgroundWorker.RunWorkerAsync(input_param);
	}
}

//取消任务
private void btnRun_Click(object sender, EventArgs e)
{
	if (backgroundWorker.WorkerSupportsCancellation == true)
    {
         backgroundWorker.CancelAsync();
    }
}

// 后台执行的任务
private void backgroundWorker_DoWork(object? sender, DoWorkEventArgs e)
{
    //后台任务接收传入的参数
    string input_param = e.Argument.ToString();
    
    //后台执行任务代码
    BackgroundWorker worker = sender as BackgroundWorker;
    for (int i = 1; i <= 10; i++)
    {
       if (worker.CancellationPending == true)
       {
           e.Cancel = true;
           break;
       }
       else
       {
          // Perform a time consuming operation and report progress.
          system.Threading.Thread.Sleep(500);
          worker.ReportProgress(i * 10); //报告执行进度，触发ProgressChanged事件
        }
    }   
}
//更新UI介面任务执行进度
//运行在UI线程
private void BackgroundWorker_ProgressChanged(object? sender, ProgressChangedEventArgs e)
{
    //获取执行进度 int型 e.ProgressPercentage
	this.progressBar1.Value = e.ProgressPercentage;
}

//后台任务执行完成事件处理程序
//运行UI线程
private void BackgroundWorker_RunWorkerCompleted(object? sender, RunWorkerCompletedEventArgs e)
{
	this.progressBar1.Value = 100;          
}