How to display progressbar if waithandle is used

frmProgressBar.show();
int successOrFail = PerformSynchronousActionUsingWaitHandle();
frmProgressBar.close();
frmMainScreen.show();

public event EventHandler<WorkCompleteArgs> WorkComplete;
    private void StartClick(object sender, EventArgs e)
    {
        //hook a complete event
        this.WorkComplete += new EventHandler(OnWorkComplete);

        //do start code

        //run the PerformSynchronousActionUsingWaitHandle process in a thread
        Thread thread = new Thread(new ThreadStart(PerformSynchronousActionUsingWaitHandle));
        thread.Start();
    }
    private void OnWorkComplete(object sender, EventArgs e)
    {
        //cross thread
        if (this.InvokeRequired)
        {
            this.BeginInvoke(new EventHandler(OnWorkComplete), new object[] { sender, e });
            return;
        }

        //un hook
        this.WorkComplete -= new EventHandler(OnWorkComplete);

        //do complete code

    }
    private void PerformSynchronousActionUsingWaitHandle()
    {
        Thread.Sleep(1000);
        if (WorkComplete != null)
        {
            //use event args to return the functions result if needed.
            WorkComplete(this, new WorkCompleteArgs(true));
        }
    }

    public class WorkCompleteArgs
    {
         public WorkState {get;private set;}
         public WorkCompleteArgs(bool workState)
         {
             this.WorkState = workState;
         }
    }