user defined window message

[=?Utf-8?B?TmF0aGFuIFNtaXRo?=]

I have an app that has several background threads running, and I want to use
a user-defined message to tell the main form that I want it to update a
object it created on startup.

I know this capability is in VC++ using the RegisterMessage and PostMessage
functions, but is there anything like this in VB.net?

Thanks.

[Tom Shelton]

On 2008-01-24, Nathan Smith <Na*********@discussions.microsoft.comwrote:

I have an app that has several background threads running, and I want to use
a user-defined message to tell the main form that I want it to update a
object it created on startup.

I know this capability is in VC++ using the RegisterMessage and PostMessage
functions, but is there anything like this in VB.net?

Thanks.

You can certainly use RegisterMessage and PostMessge from VB.NET using
P/Invoke - but, wouldn't it be simpler to just let your background
threads fire an event back to the main thread?

--
Tom Shelton

[Bill McCarthy]

"Tom Shelton" <to*********@YOUKNOWTHEDRILLcomcast.netwrote in message
news:Ov**************@TK2MSFTNGP03.phx.gbl...

On 2008-01-24, Nathan Smith <Na*********@discussions.microsoft.comwrote:

>I have an app that has several background threads running, and I want to
use
a user-defined message to tell the main form that I want it to update a
object it created on startup.

I know this capability is in VC++ using the RegisterMessage and
PostMessage
functions, but is there anything like this in VB.net?

Thanks.

You can certainly use RegisterMessage and PostMessge from VB.NET using
P/Invoke - but, wouldn't it be simpler to just let your background
threads fire an event back to the main thread?

The thing to be wary of when using events or a direct notification is that
the call will then need to be marshalled over to the UI thread. This can be
achieved a couple of ways, such as using the BackgroundWorker component for
the background threads, or using normal threading and then doing an
Control.Invoke call to get the message onto the main thread.

[Herfried K. Wagner [MVP]]

"Nathan Smith" <Na*********@discussions.microsoft.comschrieb::

>I have an app that has several background threads running, and I want to
use
a user-defined message to tell the main form that I want it to update a
object it created on startup.

I know this capability is in VC++ using the RegisterMessage and
PostMessage
functions, but is there anything like this in VB.net?

You do not even need 'RegisterWindowMessage' if you are sending messages
inside your application. Instead, you can define your own messages with
message codes in the range &H8000 through &HBFFF.

However, I am just curious why you are not using
'Control.Invoke'/'Control.BeginInvoke'/'Control.InvokeRequired' instead to
access the controls from within the threads.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>