Private button1 As MyButton
    Private Sub button1_Click(sender As Object, e As EventArgs)
        Using myProcess As New Process()
            Dim myProcessStartInfo As New ProcessStartInfo("mspaint")
            myProcess.StartInfo = myProcessStartInfo
            myProcess.Start()
            AddHandler myProcess.Exited, AddressOf MyProcessExited
            ' Set 'EnableRaisingEvents' to true, to raise 'Exited' event when process is terminated.
            myProcess.EnableRaisingEvents = True
            ' Set method handling the exited event to be called  ;
            ' on the same thread on which MyButton was created.
            myProcess.SynchronizingObject = button1
            MessageBox.Show("Waiting for the process 'mspaint' to exit....")
            myProcess.WaitForExit()
        End Using
    End Sub

    Private Sub MyProcessExited(source As Object, e As EventArgs)
        MessageBox.Show("The process has exited.")
    End Sub
End Class

Public Class MyButton
    Inherits Button

End Class

process1.StartInfo.Domain = ""
process1.StartInfo.LoadUserProfile = False
process1.StartInfo.Password = Nothing
process1.StartInfo.StandardErrorEncoding = Nothing
process1.StartInfo.StandardOutputEncoding = Nothing
process1.StartInfo.UserName = ""
process1.SynchronizingObject = Me