VB.net Multithreading Problem

[thowle]

Okay, I'm sure there is a very simple solution to my problems here and I am
just too tired, but then again maybe not.

Here is an example of my code:
Dim Conn_Thrd as new system.threadin g.thread(addres sof connecttoserver ())

public sub connecttoserver ()
'This works good
Treeview1.nodes .add("Test Node")

'This doesnt
clrnd()

'Neither does this
me.treeview1.in voke(clrnd)
end sub

'This ONLY works good when it is called inside the thread containing the
treeview1 control.
public function clrnd()
Treeview1.nodes .clear()
end sub


'This works good
Private sub Button1_click (...) handles button1.click
clrnd()
end sub

'This works good
Private sub Button2_click (...) handles button2.click
Conn_Thrd = new system.threadin g.thread(addres sof connecttoserver ())
Conn_Thrd.start ()
end sub


Please help :)

Thanks,
Travis

[Calvin Luttrell]

Re: VB.net Multithreading Problem

Travis,

You need to setup a Delegate then call the delegate function from your invoke. You're on the right track for sure.

look at:

http://groups-beta.google.com/group/microsoft.public.dotnet.framework.windowsforms.controls/browse_thread/thread/a9a0dde7d1a9d59d/7bea5bacc8070fd3?q=treeview1.invoke&_done=%2Fgroups%3Fq%3Dtreeview1.invoke%26hl%3Den%26lr%3D%26sa%3DN%26tab%3Dwg%26&_doneTitle=Back+to+Search&&d#7bea5bacc8070fd3

https://www.projectthunder.com

-Calvin Luttrell
Projectthunder. com, Inc.


"thowle" <thowle@brtc.ne t> wrote in message news:D8F272FA-7993-4217-9F1C-B89DC76AA9F1@mi crosoft.com...[color=blue]
> Okay, I'm sure there is a very simple solution to my problems here and I am
> just too tired, but then again maybe not.
>
> Here is an example of my code:
> Dim Conn_Thrd as new system.threadin g.thread(addres sof connecttoserver ())
>
> public sub connecttoserver ()
> 'This works good
> Treeview1.nodes .add("Test Node")
>
> 'This doesnt
> clrnd()
>
> 'Neither does this
> me.treeview1.in voke(clrnd)
> end sub
>
> 'This ONLY works good when it is called inside the thread containing the
> treeview1 control.
> public function clrnd()
> Treeview1.nodes .clear()
> end sub
>
>
> 'This works good
> Private sub Button1_click (...) handles button1.click
> clrnd()
> end sub
>
> 'This works good
> Private sub Button2_click (...) handles button2.click
> Conn_Thrd = new system.threadin g.thread(addres sof connecttoserver ())
> Conn_Thrd.start ()
> end sub
>
>
> Please help :)
>
> Thanks,
> Travis[/color]

[Jon Skeet [C# MVP]]

Re: VB.net Multithreading Problem

thowle <thowle@brtc.ne t> wrote:[color=blue]
> Okay, I'm sure there is a very simple solution to my problems here and I am
> just too tired, but then again maybe not.[/color]

See http://www.pobox.com/~skeet/csharp/t...winforms.shtml

Note that even when it *was* working for you, there's no guarantee
about it - you really shouldn't touch the UI at all from a non-UI
thread.

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[thowle]

RE: VB.net Multithreading Problem

Okay, here is what I've done now. I created a class called "ConnectToServe r"

in that class, it will fire off an event called "ConnectComplet e"

In the mainform that contains GUI I have the sub to handle the event, and I
have it calling a function "GetServerList" . However, it is still calling it
from inside the thread inwhich does not contain the GUI therefore it fails,
EVEN if i have a treeview1.invok e(GetServerList ()).

How can I get this to work?

"thowle" wrote:
[color=blue]
> Okay, I'm sure there is a very simple solution to my problems here and I am
> just too tired, but then again maybe not.
>
> Here is an example of my code:
> Dim Conn_Thrd as new system.threadin g.thread(addres sof connecttoserver ())
>
> public sub connecttoserver ()
> 'This works good
> Treeview1.nodes .add("Test Node")
>
> 'This doesnt
> clrnd()
>
> 'Neither does this
> me.treeview1.in voke(clrnd)
> end sub
>
> 'This ONLY works good when it is called inside the thread containing the
> treeview1 control.
> public function clrnd()
> Treeview1.nodes .clear()
> end sub
>
>
> 'This works good
> Private sub Button1_click (...) handles button1.click
> clrnd()
> end sub
>
> 'This works good
> Private sub Button2_click (...) handles button2.click
> Conn_Thrd = new system.threadin g.thread(addres sof connecttoserver ())
> Conn_Thrd.start ()
> end sub
>
>
> Please help :)
>
> Thanks,
> Travis[/color]

[Jon Skeet [C# MVP]]

RE: VB.net Multithreading Problem

thowle <thowle@brtc.ne t> wrote:[color=blue]
> Okay, here is what I've done now. I created a class called "ConnectToServe r"
>
> in that class, it will fire off an event called "ConnectComplet e"
>
> In the mainform that contains GUI I have the sub to handle the event, and I
> have it calling a function "GetServerList" . However, it is still calling it
> from inside the thread inwhich does not contain the GUI therefore it fails,
> EVEN if i have a treeview1.invok e(GetServerList ()).
>
> How can I get this to work?[/color]

You need to create a delegate from GetServerList, not call it directly.

Could you post a short but complete program which demonstrates the
problem?

See http://www.pobox.com/~skeet/csharp/complete.html for details of
what I mean by that.

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[thowle]

RE: VB.net Multithreading Problem

Bacically, here is the concept of my application in a smaller form.
(Not all of it is complete)

private sub Button1_click(. ..) handles button1.click
AddHandler Connect.Connect ed, AddressOf Connected

Dim ConnectThread as new system.threadin g.thread(addres s of Connect)
ConnectThread.s tart()
end sub

Sub Connected()
treeview1.invok e(GetServerList ())
End sub

Public function GetServerList()
....access database....
treeview1.nodes .add("Value")
....close recordset, and db conn....
end function



Public Class Connect
Public Event Connected()
....connect to server....
....yay, we are connected :)....
RaiseEvent Connected()
End class

Thats about it.




"Jon Skeet [C# MVP]" wrote:
[color=blue]
> thowle <thowle@brtc.ne t> wrote:[color=green]
> > Okay, here is what I've done now. I created a class called "ConnectToServe r"
> >
> > in that class, it will fire off an event called "ConnectComplet e"
> >
> > In the mainform that contains GUI I have the sub to handle the event, and I
> > have it calling a function "GetServerList" . However, it is still calling it
> > from inside the thread inwhich does not contain the GUI therefore it fails,
> > EVEN if i have a treeview1.invok e(GetServerList ()).
> >
> > How can I get this to work?[/color]
>
> You need to create a delegate from GetServerList, not call it directly.
>
> Could you post a short but complete program which demonstrates the
> problem?
>
> See http://www.pobox.com/~skeet/csharp/complete.html for details of
> what I mean by that.
>
> --
> Jon Skeet - <skeet@pobox.co m>
> http://www.pobox.com/~skeet
> If replying to the group, please do not mail me too
>[/color]

[thowle]

RE: VB.net Multithreading Problem

Okay I got it working. and it was pretty wild :)

As Jon Skeet said, you must make a delegate for the GetServerList() function
as follows:

Delegate Function GetServerTView( )
Public ReadOnly fnGetServerTVie w As GetServerTView

then:

Public Sub New()
fnGetServerTVie w = New GetServerTView( AddressOf Me.GetServerLis t)
end Sub

from here, you can call this from any thread as
treeview1.invok e(fnGetServerTV iew)!


Thx for help yall :)

"thowle" wrote:
[color=blue]
> Bacically, here is the concept of my application in a smaller form.
> (Not all of it is complete)
>
> private sub Button1_click(. ..) handles button1.click
> AddHandler Connect.Connect ed, AddressOf Connected
>
> Dim ConnectThread as new system.threadin g.thread(addres s of Connect)
> ConnectThread.s tart()
> end sub
>
> Sub Connected()
> treeview1.invok e(GetServerList ())
> End sub
>
> Public function GetServerList()
> ....access database....
> treeview1.nodes .add("Value")
> ....close recordset, and db conn....
> end function
>
>
>
> Public Class Connect
> Public Event Connected()
> ....connect to server....
> ....yay, we are connected :)....
> RaiseEvent Connected()
> End class
>
> Thats about it.
>
>
>
>
> "Jon Skeet [C# MVP]" wrote:
>[color=green]
> > thowle <thowle@brtc.ne t> wrote:[color=darkred]
> > > Okay, here is what I've done now. I created a class called "ConnectToServe r"
> > >
> > > in that class, it will fire off an event called "ConnectComplet e"
> > >
> > > In the mainform that contains GUI I have the sub to handle the event, and I
> > > have it calling a function "GetServerList" . However, it is still calling it
> > > from inside the thread inwhich does not contain the GUI therefore it fails,
> > > EVEN if i have a treeview1.invok e(GetServerList ()).
> > >
> > > How can I get this to work?[/color]
> >
> > You need to create a delegate from GetServerList, not call it directly.
> >
> > Could you post a short but complete program which demonstrates the
> > problem?
> >
> > See http://www.pobox.com/~skeet/csharp/complete.html for details of
> > what I mean by that.
> >
> > --
> > Jon Skeet - <skeet@pobox.co m>
> > http://www.pobox.com/~skeet
> > If replying to the group, please do not mail me too
> >[/color][/color]