Sending Arguments To Background Worker?

Question

Let's say I want to sent an int parameter to a background worker, how can this be accomplished?

private void worker_DoWork(object sender, DoWorkEventArgs e) {

}

I know when this is worker.RunWorkerAsync();, I don't understand how to define in worker_DoWork that it should take an int parameter.

Answer 1

You start it like this:

int value = 123;
bgw1.RunWorkerAsync(argument: value);  // the int will be boxed

and then

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.
}