Sending Arguments To Background Worker?

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.
}

You can pass multiple arguments like this.

List<object> arguments = new List<object>();
arguments.Add("first");      //argument 1
arguments.Add(new Object()); //argument 2
// ...
arguments.Add(10);           //argument n

backgroundWorker.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. 
}

You can use the DoWorkEventArgs.Argument property.

A full example (even using an int argument) can be found on Microsoft's site:

• How to: Run an Operation in the Background

Even though this is an already answered question, I'd leave another option that IMO is a lot easier to read:

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

And on the handler method:

private void WorkerDoWork(int value, string text) {
    ...
}