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Which implies that you already know of a solution and are just looking for confirmation. If your project has constraints, it helps to convey those so that you don't receive help that is of no value to you.
"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen
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DavidCrow wrote:
Which implies that you already know of a solution
Well not really, i think your somewhat tactless with your comments. What i am trying to achieve would mean someone with and existing MFC app that uses pre compiled headers AND someone that has no need for MFC could equally use my class by simply adding an MFC #define.
I don't know for sure that this is possible, but it does seem logical.
 Carl
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crandall wrote:
Well not really, i think your somewhat tactless with your comments.
Perhaps you misunderstood. A suggestion was given to you and you stated that "That's not really the solution i am looking for." That implies, at least to me, that you already know of a solution.
If you've been on the CP forums for any amount of time at all, you will have noticed a trend among posters where they provide as little information as possible about their problem, and the thread drags on for several dozen posts. If they had laid the problem out in as much detail as possible from the beginning, a lot of time/posts/questions could have been avoided. That is what was meant by my "If your project has constraints, it helps to convey those so that you don't receive help that is of no value to you." reply. I do not see how you can consider that "tactless."
crandall wrote:
...someone that has no need for MFC could equally use my class by simply adding an MFC #define.
If someone had no need for MFC, why would they add an MFC #define? That does not seem logical.
"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen
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I have a class.
I want to use the class in a standard win32 dll and a project built with MFC.
If i don't include the stdafx.h in the class, the MFC project complains i can't see the precompiled headers.
I would prefer not to turn off precompiled headers in the MFC project.
I don't want to include them for applications that will usr the class that do not rely on MFC.
I am hoping to find a preprocessor command i can include in the class to minimize the class user changing anything.
thanks - Carl
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thanks for that Christian, if it comes to it i'll have to resort to this but i'm trying to find a way to avoid it and primarily put the burden on the class itself.
Regards
Carl
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try
#if defined MFC
#include "stdafx.h"
#endif
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exactly the same error message
Carl
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What is the problem that you're having with the standard DLL? I have MFC projects that link in outside DLLs without any problems. The MFC apps all use precompiled headers and include stdafx.h. Then later in the stdafx.h I include the appropriate header file for the standard DLL without any issues.
I don't think conditionally including stdafx.h is the answer. More likely you will want to keep this for all builds and fix the underlying problem elsewhere.
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There is no problem with the standard dll.
I have a class.
I want to use the class in a standard win32 dll and a project built with MFC.
If i don't include the stdafx.h in the class, the MFC project complains i can't see the precompiled headers.
I would prefer not to turn off precompiled headers in the MFC project.
I don't want to include them for applications that will usr the class that do not rely on MFC.
I am hoping to find a preprocessor command i can include in the class to minimize the class user changing anything.
thanks - Carl
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What environment are trying to use the class? First of all there is the class, its definition and the user of the class. These three may all reside in the same application/build and they might not.
There a few possibilities. Which are you using?
1. Class and user within same MFC project.
2. Class and user within same non-MFC project.
3. Class in MFC Extension DLL. Users must be an MFC project.
4. Class in MFC Regular DLL. Users can either be MFC or non-MFC.
5. Class in non-MFC regular DLL. Users can either be MFC or non-MFC.
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Hi,
i have an application that creates controls on the fly on a dialog. Say a button and a combo box. I wan to handle the events in the pretranslate message of the parent(dialog in my case)so what i do is override the mydialog::PreTranslateMessage(MSG *pMsg) as below:
if(pMsg->message==WM_KEYDOWN)
{
if(pMsg->wParam==VK_RETURN)
{ pMsg->wParam=VK_TAB;
AfxMessageBox(_T("return was pressed"));
}
else
{
AfxMessageBox(_T("some key was pressed"));
}
}
else if(pMsg->message==WM_COMMAND)
{
if(HIWORD(pMsg->wParam) == BN_CLICKED)
{
CString Tmp = _T("Button Clicked was :");
Tmp.Format(_T("%s%d"),Tmp , LOWORD(wParam) ) ;
AfxMessageBox(Tmp);
}
else if (HIWORD(pMsg->wParam) == CBN_SELCHANGE)
{
CString Tmp = _T("Button Clicked was :");
Tmp.Format(_T("%s%d"),Tmp , LOWORD(wParam) ) ;
AfxMessageBox(Tmp);
}
}
return CDialog::PreTranslateMessage(pMsg);
}
Now if the child control - a button is clicked which is an object of CButton ( no subclassing done) should nt the dialog recieve a notification and therefore shouldnt the pretranslatemessage be invoked??
Thanks in advance,
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Nope!
Child controls are also windows. So when you click a CButton control, the control will handle the message rather then passing it on to the parent window.
A student knows little about a lot.
A professor knows a lot about little.
I know everything about nothing.
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thanks for the answer.
But this is what i understand about the message handling mechanism of MFC.
When a control say a button is clicked it invokes its own wndproc which does what ever is required( say showing it in depressed state). Thiis because every control is actually a window.And then it sends anotification to the parent WM_COMMAND( in this case with msg as BN_CLICKED). Right? If this was the case then i Should be able to handle BN_CLICKED in parent.
Please correct me if i am wrong.
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I think I got it, BN_CLICKED is a notification, not a command, and will be received into a WM_NOTIFY message.
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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You can process the message in the parent window. The only thing you have to do is map a message handler to the desired action in your windows message map:
<br />
BEGIN_MESSAGE_MAPE(YourWindow, DerivedFrom)<br />
ON_BN_CLICKED(IDD_YOUR_BUTTON_ID, memberfxn)<br />
END_MESSAGE_MAP()<br />
Hope this helps 
A student knows little about a lot.
A professor knows a lot about little.
I know everything about nothing.
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"You can process the message in the parent window. The only thing you have to do is map a message handler to the desired action in your windows message map:
BEGIN_MESSAGE_MAPE(YourWindow, DerivedFrom)
ON_BN_CLICKED(IDD_YOUR_BUTTON_ID, memberfxn)
END_MESSAGE_MAP() "
That is correct but my requirement is slightly different. I dont want to provide a static macro like the one above. Because my application reads what controls are to be rendered from datastructure. It reads from the datastructure that it need to create a button with xyz style , a textbox with some wdth and style etc.
Now i cannot use static statemenst as above. So what i wanted to do was intercept the default message handling mechanism. I wanted to override the pretranslate message for this and then from the MSG structure get what was the event fired and who fired it process it in pretranslatemessage and return.
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Hello,
One way to go is subclassing the button control. This[^] article will tell you more about subclassing.
The other way to go is creating your own button control by deriving your custom button class from CButton.
From there you can make the button do what you want it to do. For exemple, you can send a user defined window message to your window that'll handle the button's actions.
A student knows little about a lot.
A professor knows a lot about little.
I know everything about nothing.
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I dont wanna go subclass way because i dont wanna subclass "n" classes. Since my ui may have n differnt controls.
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i tried notify but no change. I cannot handle it still.
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I's say so, a BN_CLICKED notification, to be precise. What's your observed behavior?
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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it could be a bn_clicked, en_change, cbn_selchanged any message( command or notification ).
I donot agree that BN_CLIcKED is a wm_notify type because CButton is a standard control and not a common control.
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Maybe you're right, but I'd try anyway, it's a few of lines of code and will make you 100% sure.
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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Control notifications are handled via WM_COMMAND not WM_NOTIFY. If you wish to override the original message that caused the event like a keystroke, mouse move, etc, then you subclass the control and override the appropriate window message. If you want to override the notification (which sounds like what you want), then in the parent class (dialog) you have three options:
1. Handle the notification message. Add ON_BN_CLICKED function for example.
2. Override the OnCommand message.
Inside OnCommand you can do something like:
BOOL CYourDialog::OnCommand( WPARAM wParam, LPARAM lParam )
{
if( LOWORD(wParam) == IDC_CTRL_ID && HIWORD(wParam) == BN_CLICKED )
return( CDialog::OnCommand(wParam, lParam) );
}
3. Override PreTranslateMessage and process there.
BOOL CYourDialog::PreTranslateMessage( MSG *pMsg )
{
if( pMsg->message == WM_COMMAND )
{
if( LOWORD(pMsg->wParam) == IDC_CTRL_ID && HIWORD(pMsg->wParam) == BN_CLICKED )
}
return( CDialog::PreTranslateMessage(pMsg) );
}
I'm not sure what you're trying to do, but usually it's better to your command processing using either method 1 or 2. Rarely do I have a need to override PreTranslateMessage.
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Correct, but assume that the controls on the dialog are dynamically created such that at time of coding i dont know as to what are the controls on the dialog. So i cannot provide the macro ON_BN_CLIKCED(btnid, handler).
The reason i want to over ride the pretranslatemessage is to catch what ever goes thru the message loop filter the messages i am intersted in by using and ifelse construct like you mentioned. But the main question is my handler in pretranslate never gets invoked Why???
Cmydialog::PreTranslateMessage(MSG *msg)
{
if( pMsg->message == WM_COMMAND )
{
if(LOWORD(pMsg->wParam)==IDC_CTRL_ID && HIWORD(pMsg->wParam)==BN_CLICKED)
{
UINT controlID = LOWORD(pMsg->wParam);
if (controlID == someidofinterest)
{
//do what i want it to do
}
}
}
}
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Overriding OnCommand is the correct place to do this.
Why isn't PreTranslateMessage being called?
I had to think about this for a bit and reach back into the message loop days. PreTranslateMessage is not called for every type of message sent to a window. It is primarily a pre-cursor beforing calling the API function TranslateMessage.
TranslatesMessage's primary function is to convert key strokes into WM_CHAR messages or into command accelerators.
MFC's message loop, in a nutshell, looks like this:
while( GetMessage(pMsg) )
{
if( ! AfxPreTranslateMessage(pMsg) )
{
::TranslateMessage(pMsg);
::DispatchMessage(pMsg);
}
}
The key thing to note here as the GetMessage does not return for every message received by the application. It only returns for WM_QUIT, posted messages (I think), and keyboard handling. WM_COMMAND messages are sent directly to the window procedure from within GetMessage. The reason for this is that there is no translation necessary.
Think of it this way. The purpose of PreTranslateMessage/TranslateMessage is not to perform some action when a message is received. That's what the appropriate message handlers are for (like OnCommand). It's job is to convert message IDs from one to another as needed. For example if you press "Ctrl+N" it converts the WM_KEYUP to WM_COMMAND (ID_FILE_NEW).
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