How to wait correctly until BackgroundWorker completes?

Try using the AutoResetEvent class like this:

var doneEvent = new AutoResetEvent(false);var bw = new BackgroundWorker();bw.DoWork += (sender, e) =>{  try  {    if (!e.Cancel)    {      // Do work    }  }  finally  {    doneEvent.Set();  }};bw.RunWorkerAsync();doneEvent.WaitOne();

Caution: You should make sure that doneEvent.Set() is called no matter what happens. Also you might want to provide the doneEvent.WaitOne() with an argument specifying a timeout period.

Note: This code is pretty much a copy of Fredrik Kalseth answer to a similar question.

To wait for a background worker thread (single or multiple) do the following:

1. Create a List of Background workers you have programatically created:

   private IList<BackgroundWorker> m_WorkersWithData = new List<BackgroundWorker>();

2. Add the background worker in the list:

   BackgroundWorker worker = new BackgroundWorker();worker.DoWork += new DoWorkEventHandler(worker_DoWork);worker.ProgressChanged += new ProgressChangedEventHandler(worker_ProgressChanged);worker.WorkerReportsProgress = true;m_WorkersWithData.Add(worker);worker.RunWorkerAsync();

3. Use the following function to wait for all workers in the List:

   private void CheckAllThreadsHaveFinishedWorking(){    bool hasAllThreadsFinished = false;    while (!hasAllThreadsFinished)    {        hasAllThreadsFinished = (from worker in m_WorkersWithData                                 where worker.IsBusy                                 select worker).ToList().Count == 0;        Application.DoEvents(); //This call is very important if you want to have a progress bar and want to update it                                //from the Progress event of the background worker.        Thread.Sleep(1000);     //This call waits if the loop continues making sure that the CPU time gets freed before                                //re-checking.    }    m_WorkersWithData.Clear();  //After the loop exits clear the list of all background workers to release memory.                                //On the contrary you can also dispose your background workers.}

BackgroundWorker has a completion event. Instead of waiting, call your remaining code path from the completion handler.