Waiting for threaded work method to complete inside a threaded loop

[pel11]

I am using a threaded loop to spawn a work method, and then wait for the work method to complete before cycling another loop iteration. However, when I specify 4 steps in the loop, I am only getting two steps performed. Is there anything fundamentally wrong in this code? Any better way to do this.

Public AllThreadsDone As New System.Threading.AutoResetEvent(False)
AllThreadsDone.Set


Dim t = New Thread(AddressOf ThreadedLoop)
t.IsBackground = True
t.SetApartmentState(ApartmentState.STA)
threadList.Add(t)

Sub ThreadedLoop()

  For j = 0 to 3
    Dim t = New Thread(AddressOf DoWork)
    t.IsBackground = True
    t.SetApartmentState(ApartmentState.STA)
    threadList.Add(t)

    Dim t = New Thread(AddressOf waitforthreadcompletion)
    t.IsBackground = True
    t.SetApartmentState(ApartmentState.STA)
    t.Start()

    AllThreadsDone.WaitOne()

  Next j

End Sub

Sub DoWork()

  Thread.Sleep(10000
  WorkThreadDone.Set()

End Sub

Private Sub waitforthreadcompletion()

  Try
retry:
  For Each t In threadList
    If t.IsAlive = True Then GoTo retry
  Next
  AllThreadsDone.Set()
  Exit Sub
  Catch
     GoTo retry
  End Try

End Sub