how to create a form having a list box and updating it from another form using multi threading and delegates

FORM1 CODE

private void button1_Click(object sender, EventArgs e)
        {
            Form2 form2 = new Form2(this);//this is required to update list by calling public method in Form1. Not required for event based update
            form2.OnMyForm2Event += AddToListViewByListeningToEvent;
            form2.Show();
        }

        public void AddToListUsingPublicProperty(string item)
        {
            listBox1.Invoke(new MethodInvoker(() =>
            {
                listBox1.Items.Add(item);
            }));
        }


        private void AddToListViewByListeningToEvent(object sender, MyEventArgs e)
        {
            listBox1.Invoke( new MethodInvoker( () =>
            {
                listBox1.Items.Add(e.EventData);
            }));
        }

------------------------------------------------------------------------
FORM2 CODE
-------------------------------------------------------------------------------
public partial class Form2 : Form
{

public event EventHandler<myeventargs> OnMyForm2Event;
BackgroundWorker _bw = new BackgroundWorker();
public Form1 _Form1;

public Form2()
{
InitializeComponent();
}

public Form2(Form1 form1)
{
InitializeComponent();
this._Form1 = form1;
_bw.DoWork += DoBackgroundWork;
_bw.RunWorkerCompleted += OnRunWorkerCompleted;
}
#region BackgroundWorker

private void btnUsingBackgroundWorker_Click(object sender, EventArgs e)
{
_bw.RunWorkerAsync();
}

private void DoBackgroundWork(object sender, DoWorkEventArgs e)
{

//Do some heavy duty operations
if (OnMyForm2Event != null)
OnMyForm2Event(this, new MyEventArgs("ItemFromForm2UsingBGThread"));

//Add item by calling public property on Form1
_Form1.AddToListUsingPublicProperty("ItemAddedDirectlyByCallingPublicMethod-BackGroundWorker");
}

private void OnRunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
_Form1.AddToListUsingPublicProperty("ItemAddedWhenBackgroundworkerFinisheswork");
}
#endregion
#region Thread
private void btnUpdateUsingThread_Click(object sender, EventArgs e)
{
Thread t = new Thread(PerformActionOnThread);
t.Start("ItemFromForm2UsingThread");

}

private void PerformActionOnThread(object value)
{
//Add using Event
if (OnMyForm2Event != null)
OnMyForm2Event(this, new MyEventArgs(value.ToString()));

//Add item by calling public property on Form1
_Form1.AddToListUsingPublicProperty("ItemAddedDirectlyByCallingPublicMethod-Thread");
}

#endregion

#region Task
private void btnUsingTask_Click(object sender, EventArgs e)
{
Task.Factory.StartNew(() => _Form1.AddToListUsingPublicProperty("ItemAddedByTask")).
ContinueWith(x => _Form1.AddToListUsingPublicProperty("ItemAddedOnTaskCompletion"));
}
#endregion
}

public class MyEventArgs : EventArgs
{
public string EventData { get; set; }
public MyEventArgs(string eventData)
{
EventData = eventData;
}
}