向背景工作者发送参数？

Question

假设我想将int参数发送给后台工作者，这如何完成？private void worker_DoWork(object sender, DoWorkEventArgs e) {}我知道什么时候是worker.RunWorkerAsync（）;，我不明白如何在worker_DoWork中定义它应该采用int参数。

Answer 1

您可以这样启动：

int value = 123;

bgw1.RunWorkerAsync(argument: value);  // the int will be boxed

接着

private void worker_DoWork(object sender, DoWorkEventArgs e) 

{

   int value = (int) e.Argument;   // the 'argument' parameter resurfaces here

   ...

   // and to transport a result back to the main thread

   double result = 0.1 * value;

   e.Result = result;

}

// the Completed handler should follow this pattern 

// for Error and (optionally) Cancellation handling

private void worker_Completed(object sender, RunWorkerCompletedEventArgs e) 

{

  // check error, check cancel, then use result

  if (e.Error != null)

  {

     // handle the error

  }

  else if (e.Cancelled)

  {

     // handle cancellation

  }

  else

  {          

      double result = (double) e.Result;

      // use it on the UI thread

  }

  // general cleanup code, runs when there was an error or not.

}

Answer 2

尽管这是一个已经回答的问题，但我还是会提出另一个选择，即IMO更容易阅读：

BackgroundWorker worker = new BackgroundWorker();

worker.DoWork += (obj, e) => WorkerDoWork(value, text);

worker.RunWorkerAsync();

并在处理程序方法上：

private void WorkerDoWork(int value, string text) {

    ...

}

Answer 3

您可以像这样传递多个参数。

List<object> arguments = new List<object>();

                    arguments.Add(argument 1);

                    arguments.Add(argument 1);

                    arguments.Add(argument n);

                    backgroundWorker2.RunWorkerAsync(arguments);

private void worker_DoWork(object sender, DoWorkEventArgs e) {

  List<object> genericlist = e.Argument as List<object>;

  extract your multiple arguments from this list and cast them and use them. 

}