>From the c# application side, I have to take the WM_ASYNCDATA_START on

"minimega" <minimega@libero.it> wrote in message
news:1130778925.684641.221020@g14g2000cwa.googlegroups.com...
> Hello to all NG.
>
> Startint from the (working) "Asynchronous callbacks from native Win32
> code" MSDN example, I modified the source code adding a second instance
> of "public MyMessageWnd msgWnd;", calling them msgWnd1 and msgWnd2 (I
> can observe that two classes have different .hWnd values).
>
> Then I modified the C++ class, adding 2 new WM_ events
> (WM_ASYNCDATA_START and WM_ASYNCDATA_STOP) and the code in
> RandomWndDataFeeder like this:
>
> DWORD WINAPI RandomWndDataFeeder (LPVOID lpParameter)
> {
>
> if(g_hWndManaged2 != NULL)
> {
> PostMessage(g_hWndManaged2, WM_ASYNCDATA_START, 0,
> ::GetTickCount());//0);
> //::Sleep(0);
> }
>
> for(int i = 0; i < g_dwCicli; i++)
> {
> PostMessage(g_hWndManaged1, WM_ASYNCDATA_RECEIVED, 0,
> ::GetTickCount());//(LPARAM)g_pszWndSource);
> //::Sleep(0);
> }
>
> if(g_hWndManaged2 != NULL)
> {
> PostMessage(g_hWndManaged2, WM_ASYNCDATA_STOP, 0,
> ::GetTickCount());//0);
> //::Sleep(0);
> }
>
> return 0L;
> }
>
> The function
> RANDOMDATA_API void StartWndCommunication (DWORD messageType, HWND
> hWnd1, HWND hWnd2, DWORD cicli)
>
> now has 2 HWND parameters, one for the first managed class and one for
> the second managed class and is called by the managed application with:
> UnmanagedWndAPI.StartWndCommunication(msgWnd1.Hwnd, msgWnd2.Hwnd,
> 1000);
>
> What I doing? I want to demonstrate that with PostMessage the message
> queue is asyncronous, so the C++ "for" cicle, adds the messages as
> quick as possible, then ends BEFORE the C# appl has readed all the
> messages in his queue (in fact C++ adds in the queue at least 8-9
> messages in 1 milliseconds, and the maneged application needs at least
> 30-35 milliseconds to get the message and add it to the list).
>
>>From the c# application side, I have to take the WM_ASYNCDATA_START on
> the second class instance, then 1000 WM_ASYNCDATA_RECEIVED in the
> first class instance, and finally a WM_ASYNCDATA_STOP in the second
> class instance.
>
> Every message received is displayes on a list control. What happens if
> I run the application? I get the messages in the list, clear! However
> the WM_ASYNCDATA_STOP message is displayed as last item in the list,
> after the last WM_ASYNCDATA_RECEIVED: this is wrong. If I send 2
> different hWnd to C++ application, the 2 queues are separated, and I
> have to receive the WM_ASYNCDATA_STOP in the second class instance
> before then first class instance ends his messages.
>
> If I create 2 different exe, and I pass to C++ the hWnd of the class
> instance of each different exe, it works! in second exe I get the
> WM_ASYNCDATA_STOP message when the first exe is receiving the 8th-9th
> WM_ASYNCDATA_RECEIVED message (and there are 1000 messages in his
> queue!)
>
> Is seems that different hWnd queue in the same exe are working in
> syncronous mode each other.
>
> Who can explain me better how Windows Messages works?
>
> Thanks.
>

> Sure, two windows in the same application do work synchronously to each
> other. Read the code for any C/C++ Hello, World program. There's a
> *single* message loop that calls GetMessage() to get the next message
> from the *application message queue* and dispatch it to the right
> window. I suppose that you could try to use threading to create two
> separate message loops, but I'm not sure why you'd do this and there
> would be numerous synchronization issues to be handled.
>
> Paul T.
>

"Max" <spam@minimega@libero.it> wrote in message
news:e12jlSu3FHA.3260@TK2MSFTNGP10.phx.gbl...
> Hi Paul,
> thanks for your reply. You give me a reason why, so I don't need to go
> over! In fact I've tried to make the window class instance in two
> separated threads, but the result is that I get no callback to the wndproc
> function! So, isn't possible to speak in an asyncronous way with two
> windows owned by the same application (exe) with the windows message way.
>
> Thanks,
> Massimo
>
> "Paul G. Tobey [eMVP]" <ptobey no spam AT no instrument no spam DOT com>
> ha scritto nel messaggio news:O35m9$j3FHA.2676@TK2MSFTNGP15.phx.gbl...
>> Sure, two windows in the same application do work synchronously to each
>> other. Read the code for any C/C++ Hello, World program. There's a
>> *single* message loop that calls GetMessage() to get the next message
>> from the *application message queue* and dispatch it to the right window.
>> I suppose that you could try to use threading to create two separate
>> message loops, but I'm not sure why you'd do this and there would be
>> numerous synchronization issues to be handled.
>>
>> Paul T.
>>
>
>

> Not completely asynchronous, no. There's no good reason that I can think of
> for doing that. The user interface is really a synchronous object, anyway.
> If you have something that wants to happen in the background, use a thread,
> but don't try to associate that with a window. Just have it do its job and
> use an event or post a message to the main application, when the process is
> done.
>
> Paul T.
>