Notify user when thread has started and when it has finished?

[kutlesh]

Learning this VB.NET stuff and I am still not sure how to notify properly the user when exporting to excel has started and when it has finished.

I have this code:

Dim finished as Boolean = true

private sub exportToExcel()
 ' exporting code
end sub

Private Sub exportToExcelBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles exportToExcelBtn.Click
        finished = False
        statusBarTB.Text = "Exporting data to Excel file. "

        thread = New System.Threading.Thread(AddressOf exportToExcel)
        thread.Start()

        While Not thread.IsAlive
            statusBarTB.Text = "Finished recording data to Excel file! "
        End While
    End Sub

I tried with this "finished" boolean flag but the window gets stuck until the export has finished, which is not what I want. Why do i use thread in the first place if it freezes the window thread.

How can I properly notify user when thread has started and has finished?

Does VB.NET Threading API have stuff like addEventListener with which I can add functions and execute those on certain events?