Question

我想问一下如何通过Window窗体中的代码添加后台工作组件？请注意，我知道如何从组件托盘中的ToolBox添加它，但我想通过代码添加它。任何示例代码都表示赞赏。

Answer 1

DoWork在不同的线程中，向主线程报告进度并取消异步进程是BackgroundWorker中最重要的功能。下面的例子非常清楚地展示了这三个功能。网上有大量的例子。

using System;
using System.Threading;
using System.ComponentModel;

class Program
{
  static BackgroundWorker _bw;

  static void Main()
  {
    _bw = new BackgroundWorker
    {
      WorkerReportsProgress = true,
      WorkerSupportsCancellation = true
    };
    _bw.DoWork += bw_DoWork;
    _bw.ProgressChanged += bw_ProgressChanged;
    _bw.RunWorkerCompleted += bw_RunWorkerCompleted;

    _bw.RunWorkerAsync ("Hello to worker");

    Console.WriteLine ("Press Enter in the next 5 seconds to cancel");
    Console.ReadLine();
    if (_bw.IsBusy) _bw.CancelAsync();
    Console.ReadLine();
  }

  static void bw_DoWork (object sender, DoWorkEventArgs e)
  {
    for (int i = 0; i <= 100; i += 20)
    {
      if (_bw.CancellationPending) { e.Cancel = true; return; }
      _bw.ReportProgress (i);
      Thread.Sleep (1000);      // Just for the demo... don't go sleeping
    }                           // for real in pooled threads!

    e.Result = 123;    // This gets passed to RunWorkerCompleted
  }

  static void bw_RunWorkerCompleted (object sender,
                                     RunWorkerCompletedEventArgs e)
  {
    if (e.Cancelled)
      Console.WriteLine ("You canceled!");
    else if (e.Error != null)
      Console.WriteLine ("Worker exception: " + e.Error.ToString());
    else
      Console.WriteLine ("Complete: " + e.Result);      // from DoWork
  }

  static void bw_ProgressChanged (object sender,
                                  ProgressChangedEventArgs e)
  {
    Console.WriteLine ("Reached " + e.ProgressPercentage + "%");
  }
}

Reference

Answer 2

创建BackgroundWorker类的实例，并为其DoWork事件添加处理程序。

如何在Windows窗体应用程序上添加后台工作程序组件？

2 个答案: