Correct thread termination

[Sir Spamallot]

Hi there,

Previously when handling the termination of threads I had just called the
abort method and caught it in a try catch block in the thread callback.
After recently learning that this was a bad way of handling thread
termination I am working on terminating threads by using ManualResetEven t's.

I have come up with the following code which appears to work very well (at
end of message). I would like to know if anyone knows of any problems that
I could encounter from this code and whether or not it is following correct
procedure.

If someone has a link to suitable reference I would be most appreciative if
you could point me toward it. Otherwise, does this code look okay?

SSA

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Private pTrdThread As Thread
Private cMREBusy As New ManualResetEven t(False)
Private cMREReady As New ManualResetEven t(True)
Private cMRETerminate As New ManualResetEven t(False)

Private Sub PictureBox1_Mou seMove(ByVal sender As Object, ByVal e As
System.Windows. Forms.MouseEven tArgs) Handles PictureBox1.Mou seMove
Call startThread(e.L ocation)
End Sub

Private Sub startThread(ByV al iParam As Object, Optional ByVal iJustAbort As
Boolean = False)
If (cMREBusy.WaitO ne(0, False)) Then
Call Console.WriteLi ne("Thread has already started...")
Call cMRETerminate.S et()
If (cMREReady.Wait One(3000, False)) Then
Call Console.WriteLi ne("Thread terminated!")
If (Not iJustAbort) Then
GoTo startThreadProc ess
End If
Else
Call Console.WriteLi ne("Could not terminate thread!")
End If
Else
startThreadProc ess:
Call Console.WriteLi ne("Starting thread!")
Call cMREReady.Reset () '//We are not ready to start again
Call cMREBusy.Set() '//We are busy now
Call cMRETerminate.R eset() '//We can be terminated again from now
pTrdThread = New Thread(New ParameterizedTh readStart(Addre ssOf
thread_Callback ))
Call pTrdThread.Star t(iParam)
End If
End Sub

Private Sub thread_Callback (ByVal iParam As Object)
Call Console.WriteLi ne("Thread started with - " & iParam.ToString & " @
" & Environment.Tic kCount)

Dim pGraGraphics As Graphics = PictureBox1.Cre ateGraphics()
Using pGraGraphics

Dim pIntCurItem As Integer
For pIntCurItem = 0 To 60
Call pGraGraphics.Dr awLine(Pens.Bla ck, CType(iParam, Point),
Point.Add(CType (iParam, Point), New Size(1, 1)))
Call Thread.Sleep(10 0)
If (cMRETerminate. WaitOne(0, False)) Then
Call Console.WriteLi ne("Thread terminating @ " &
Environment.Tic kCount)
Exit For
End If
Next

End Using

Call Console.WriteLi ne("Thread exited @ " & Environment.Tic kCount)
Call cMREReady.Set() '//We are now ready to start again
Call cMREBusy.Reset( ) '//We are not busy anymore
End Sub

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