Multi-Threaded App

[askhuy]

Hi All

Would someone please explain to me why my threads are not running at the
sametime? Here is what I don't understand. When I invoke the TestThread()
procedure, I always get the output of main thread first and then the
secondary thread's output. Shouldn't the ouput show the mixed messages



Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button1.Click
TestThread()
End Sub



Private Sub TestThread()
'Create new thread and define its starting point
Dim t As New Thread(New ThreadStart(Add ressOf DoSomeTask))
'run the new thread
t.Start()

' print some messages to screen
Dim i As Integer
For i = 1 To 1000
TextBox1.Text &= "from main thread # = " & i.ToString & vbCrLf
Next
End Sub

Sub DoSomeTask()
Dim i As Integer

For i = 1 To 1000
TextBox1.Text &= "from secondary thread # = " & i.ToString &
vbCrLf
Next
End Sub


Here are my outputs

from main thread # = 1
from main thread # = 2
from main thread # = 3
from main thread # = 4
from main thread # = 5
from main thread # = 6
from main thread # = 7
from main thread # = 8
from main thread # = 9
from main thread # = 10
from secondary thread # = 1
from secondary thread # = 2
from secondary thread # = 3
from secondary thread # = 4
from secondary thread # = 5
from secondary thread # = 6
from secondary thread # = 7
from secondary thread # = 8
from secondary thread # = 9
from secondary thread # = 10

[Michel Posseth [MCP]]

Re: Multi-Threaded App

No not in this case ,, wich is also bad coding practice for multithreading

1. ever heard of thread switching and thread prio`s ?
2. do you know that GUI controls run on the main thread ?
and dealing from sperate threads should invoke a synchronization
mechanism ?

You probably wrote this in .Net 2003 ?? as in .Net 2005 it should not be
possible to run this code

about point 1 ,,, you also probably run this on a SP system and not on a MP
system ,, however you could force a thread switch by coding some thread
sleeps in the 2 procedures . but as i said the shown code is a practicce to
show how MT should not be implemented


regards

Michel Posseth [MCP]








"askhuy" <askhuy@yahoo.c omschreef in bericht
news:%23oxAq7ys GHA.1876@TK2MSF TNGP06.phx.gbl. ..

Hi All
>
Would someone please explain to me why my threads are not running at
the sametime? Here is what I don't understand. When I invoke the
TestThread() procedure, I always get the output of main thread first and
then the secondary thread's output. Shouldn't the ouput show the mixed
messages
>
>
>
Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button1.Click
TestThread()
End Sub
>
>
>
Private Sub TestThread()
'Create new thread and define its starting point
Dim t As New Thread(New ThreadStart(Add ressOf DoSomeTask))
'run the new thread
t.Start()
>
' print some messages to screen
Dim i As Integer
For i = 1 To 1000
TextBox1.Text &= "from main thread # = " & i.ToString & vbCrLf
Next
End Sub
>
Sub DoSomeTask()
Dim i As Integer
>
For i = 1 To 1000
TextBox1.Text &= "from secondary thread # = " & i.ToString &
vbCrLf
Next
End Sub
>
>
Here are my outputs
>
from main thread # = 1
from main thread # = 2
from main thread # = 3
from main thread # = 4
from main thread # = 5
from main thread # = 6
from main thread # = 7
from main thread # = 8
from main thread # = 9
from main thread # = 10
from secondary thread # = 1
from secondary thread # = 2
from secondary thread # = 3
from secondary thread # = 4
from secondary thread # = 5
from secondary thread # = 6
from secondary thread # = 7
from secondary thread # = 8
from secondary thread # = 9
from secondary thread # = 10
>
>
>
>

[Chris]

Re: Multi-Threaded App


If you are using VB 2005 have a look at
http://msdn.microsoft.com/library/de...nginvb2005.asp
for an awesome article that goes over the BackgroundWorke r. There is even
sample code.

Chris

"askhuy" <askhuy@yahoo.c omwrote in message
news:%23oxAq7ys GHA.1876@TK2MSF TNGP06.phx.gbl. ..

Hi All
>
Would someone please explain to me why my threads are not running at
the sametime? Here is what I don't understand. When I invoke the
TestThread() procedure, I always get the output of main thread first and
then the secondary thread's output. Shouldn't the ouput show the mixed
messages
>
>
>
Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button1.Click
TestThread()
End Sub
>
>
>
Private Sub TestThread()
'Create new thread and define its starting point
Dim t As New Thread(New ThreadStart(Add ressOf DoSomeTask))
'run the new thread
t.Start()
>
' print some messages to screen
Dim i As Integer
For i = 1 To 1000
TextBox1.Text &= "from main thread # = " & i.ToString & vbCrLf
Next
End Sub
>
Sub DoSomeTask()
Dim i As Integer
>
For i = 1 To 1000
TextBox1.Text &= "from secondary thread # = " & i.ToString &
vbCrLf
Next
End Sub
>
>
Here are my outputs
>
from main thread # = 1
from main thread # = 2
from main thread # = 3
from main thread # = 4
from main thread # = 5
from main thread # = 6
from main thread # = 7
from main thread # = 8
from main thread # = 9
from main thread # = 10
from secondary thread # = 1
from secondary thread # = 2
from secondary thread # = 3
from secondary thread # = 4
from secondary thread # = 5
from secondary thread # = 6
from secondary thread # = 7
from secondary thread # = 8
from secondary thread # = 9
from secondary thread # = 10
>
>
>
>

[Galen Somerville]

Re: Multi-Threaded App


"askhuy" <askhuy@yahoo.c omwrote in message
news:%23oxAq7ys GHA.1876@TK2MSF TNGP06.phx.gbl. ..

Hi All
>
Would someone please explain to me why my threads are not running at
the sametime? Here is what I don't understand. When I invoke the
TestThread() procedure, I always get the output of main thread first and
then the secondary thread's output. Shouldn't the ouput show the mixed
messages
>
>
>
Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button1.Click
TestThread()
End Sub
>
>
>
Private Sub TestThread()
'Create new thread and define its starting point
Dim t As New Thread(New ThreadStart(Add ressOf DoSomeTask))
'run the new thread
t.Start()
>
' print some messages to screen
Dim i As Integer
For i = 1 To 1000
TextBox1.Text &= "from main thread # = " & i.ToString & vbCrLf
Next
End Sub
>
Sub DoSomeTask()
Dim i As Integer
>
For i = 1 To 1000
TextBox1.Text &= "from secondary thread # = " & i.ToString &
vbCrLf
Next
End Sub
>
>
Here are my outputs
>
from main thread # = 1
from main thread # = 2
from main thread # = 3
from main thread # = 4
from main thread # = 5
from main thread # = 6
from main thread # = 7
from main thread # = 8
from main thread # = 9
from main thread # = 10
from secondary thread # = 1
from secondary thread # = 2
from secondary thread # = 3
from secondary thread # = 4
from secondary thread # = 5
from secondary thread # = 6
from secondary thread # = 7
from secondary thread # = 8
from secondary thread # = 9
from secondary thread # = 10
>
>

In your TestThread you have "from main thread # = "
Then under DoSomeTask you have "from secondary thread # = "

Isn't that a reversal of meaning?

Galen

[askhuy]

Re: Multi-Threaded App

Hi guys,

Thanks for your helps. I tried with the console windows and both threads
execute at the same time.

Regards

Sam



"Michel Posseth [MCP]" <MSDN@posseth.c omwrote in message
news:uV1%23hR0s GHA.4420@TK2MSF TNGP04.phx.gbl. ..

No not in this case ,, wich is also bad coding practice for multithreading
>
1. ever heard of thread switching and thread prio`s ?
2. do you know that GUI controls run on the main thread ?
and dealing from sperate threads should invoke a synchronization
mechanism ?
>
You probably wrote this in .Net 2003 ?? as in .Net 2005 it should not be
possible to run this code
>
about point 1 ,,, you also probably run this on a SP system and not on a
MP system ,, however you could force a thread switch by coding some thread
sleeps in the 2 procedures . but as i said the shown code is a practicce
to show how MT should not be implemented
>
>
regards
>
Michel Posseth [MCP]
>
>
>
>
>
>
>
>
"askhuy" <askhuy@yahoo.c omschreef in bericht
news:%23oxAq7ys GHA.1876@TK2MSF TNGP06.phx.gbl. ..

>Hi All
>>
> Would someone please explain to me why my threads are not running at
>the sametime? Here is what I don't understand. When I invoke the
>TestThread() procedure, I always get the output of main thread first and
>then the secondary thread's output. Shouldn't the ouput show the mixed
>messages
>>
>>
>>
> Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
>System.EventAr gs) Handles Button1.Click
> TestThread()
> End Sub
>>
>>
>>
> Private Sub TestThread()
> 'Create new thread and define its starting point
> Dim t As New Thread(New ThreadStart(Add ressOf DoSomeTask))
> 'run the new thread
> t.Start()
>>
> ' print some messages to screen
> Dim i As Integer
> For i = 1 To 1000
> TextBox1.Text &= "from main thread # = " & i.ToString & vbCrLf
> Next
> End Sub
>>
> Sub DoSomeTask()
> Dim i As Integer
>>
> For i = 1 To 1000
> TextBox1.Text &= "from secondary thread # = " & i.ToString &
>vbCrLf
> Next
> End Sub
>>
>>
>Here are my outputs
>>
>from main thread # = 1
>from main thread # = 2
>from main thread # = 3
>from main thread # = 4
>from main thread # = 5
>from main thread # = 6
>from main thread # = 7
>from main thread # = 8
>from main thread # = 9
>from main thread # = 10
>from secondary thread # = 1
>from secondary thread # = 2
>from secondary thread # = 3
>from secondary thread # = 4
>from secondary thread # = 5
>from secondary thread # = 6
>from secondary thread # = 7
>from secondary thread # = 8
>from secondary thread # = 9
>from secondary thread # = 10
>>
>>
>>
>>

>
>

[Phill W.]

Re: Multi-Threaded App

askhuy wrote:

Would someone please explain to me why my threads are not running at the
sametime? Here is what I don't understand. When I invoke the TestThread()
procedure, I always get the output of main thread first and then the
secondary thread's output. Shouldn't the ouput show the mixed messages

They /will/ run at the same time, provided each allows the other a look
in from time to time.
Add a call to ...

System.Threadin g.Thread.Sleep( 0 )

.... into each loop - this tells the thread to yield to other processes
(i.e. Threads). Without this, each Thread will "hog" the CPU, doing its
own thing until it's finished.

HTH,
Phill W.