private void buttonUpdateContacts_Click(object sender, EventArgs e)
    {
        BackgroundWorker worker = new BackgroundWorker();
        worker.WorkerReportsProgress = true;
        worker.DoWork += new DoWorkEventHandler(worker_DoWork);
        worker.ProgressChanged += new ProgressChangedEventHandler(worker_ProgressChanged);
        worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
        worker.RunWorkerAsync();
    }

    void worker_DoWork(object sender, DoWorkEventArgs e)
    {
        (sender as BackgroundWorker).ReportProgress(0, "Parsing word document...");

        WordDocumentParser wordDocumentParser;
        try
        {
            wordDocumentParser = new WordDocumentParser(Settings.Default.OohSheetLocation);
        }
        catch (FileNotFoundException exception)
        {
            e.Result = new FileNotFoundException("Could not find the word document. File path is: " + exception.FileName, exception);
            return;
        }

        List<TppContact> oohSheetContacts = wordDocumentParser.GetContacts();

        try
        {
            _contactManager = GoogleContactsManager.CreateContactsManager();
        }
        catch (InvalidCredentialsException argumentException)
        {
            e.Result = argumentException;
            return;
        }
        catch (ArgumentNullException nullArg)
        {
            e.Result = nullArg;
            return;
        }

        (sender as BackgroundWorker).ReportProgress(0, "Comparing Google contacts to the word document...");
        var comparer = new ContactComparer(oohSheetContacts, _contactManager);
        _actions = comparer.Compare();
    }

    void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        labelCurrentStatus.Text = e.UserState.ToString();
    }

    void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        if (e.Result != null)
        {
            MessageBox.Show((e.Result as Exception).Message);
        }
        else
        {
            if (_actions.Count == 0)
            {
                textBoxChanges.Text = "There are no changes to be made.";
                buttonApplyChanges.Enabled = false;
            }
            else
            {
                textBoxChanges.Text = string.Empty;
                _actions.ForEach(action => textBoxChanges.Text += action.ChangeDescription + Environment.NewLine);
                buttonApplyChanges.Enabled = true;
            }
        }
    }

    private void button2_Click(object sender, EventArgs e)
    {
        labelCurrentStatus.Text = "Updating Google...";
        _contactManager.UpdateContacts(_actions);

        labelCurrentStatus.Text = "Done.";
    }

// sample worker state class definition
internal class WorkerState
{
    public Exception ExceptionThrown { get; set; }
    public string ProgressMessage { get; set; }
    public int MaximumProgressValue { get; set; }
    public int ProgressValue { get; set; }
    public int Actions { get; set; }
}

// this would likely be initialized / reinitiatlized before the RunWorkerAsync is called
private WorkerState m_WorkerState;

private void buttonUpdateContacts_Click(object sender, EventArgs e)
{
    // for question 2) this could be convered into some form of
    // factory where providing delegates for the ProgressChange and WorkCompleted
    BackgroundWorker worker = new BackgroundWorker();

    worker.UserState = new WorkerState();

    worker.WorkerReportsProgress = true;
    worker.DoWork += new DoWorkEventHandler(worker_DoWork);
    worker.ProgressChanged += new ProgressChangedEventHandler(worker_ProgressChanged);
    worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
    worker.RunWorkerAsync();
}

void worker_DoWork(object sender, DoWorkEventArgs e)
{
    Worker worker = (sender as BackgroundWorker);
    WorkerState state = worker.UserState;

    state.UserState.ProgressMessage = "Parsing word document...";
    state.UserState.MaximumProgressValue = 100;
    state.UserState.ProgressValue = 0;

    worker.ReportProgress(0, state);

    // ...

    try
    {
        // do something
    }
    catch (InvalidCredentialsException argumentException)
    {
        e.ExceptionThrown = argumentException;
        return;
    }
    catch (ArgumentNullException nullArg)
    {
        e.ExceptionThrown = nullArg;
        return;
    }

    // ..
}