C / C++ / MFC Discussion Boards

Re: Custom controls in an exported DLL

Bartosz Bien6-Mar-03 12:33

Bartosz Bien

6-Mar-03 12:33

Have you tried InitCommonControls[Ex], AfxInitRichEdit[2]?

Regards,
BB

Re: Custom controls in an exported DLL

DREVET Olivier6-Mar-03 13:06

DREVET Olivier

6-Mar-03 13:06

Thank you for your answer BB, your advice is all right with rich edit control (with the use of AfxInitRichEdit), but the exported form view is still crashing with custom controls Frown | :-(

An assert occurs on the view creation -> hWnd is NULL in CreateDlgIndirect(). I guess that something is not properly initialized but what ? That is the question, hopping that someone could answer to it... Smile | :)

After some searches, I didn't found anything interesting about such initialisation...

Re: Custom controls in an exported DLL

Bartosz Bien7-Mar-03 0:33

Bartosz Bien

7-Mar-03 0:33

Following the initialization path, did you register your custom control classes in the DLL?

Regards,
BB

Re: Custom controls in an exported DLL

DREVET Olivier7-Mar-03 0:48

DREVET Olivier

7-Mar-03 0:48

Effectively I didn't registered it. Since this custom control works when used in the main application, I was guessing that it would dirctly run.

I'm not very close to DLLs, can you quickly explain me how to register it and why it's needed ?

Thank you very much BB, I begin to see the light at the end of the tunnel Smile | :)

Re: Custom controls in an exported DLL

Bartosz Bien7-Mar-03 1:07

Bartosz Bien

7-Mar-03 1:07

There's an important issue here: MFC extension DLLs maintain their own resource handle.

Personally I call such function in the C++ constructor of all my custom controls (I modified it slightly to fit your question):

BOOL CMyCustomCtrl::RegisterClass()<br />
{<br />
    WNDCLASS wndcls;<br />
    HINSTANCE hInst = AfxGetResourceHandle();<br />
<br />
    if(!(GetClassInfo(hInst, "MyWndClassName", &wndcls)))<br />
    {<br />
        wndcls.style            = CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS;<br />
        wndcls.lpfnWndProc      = ::DefWindowProc;<br />
        wndcls.cbClsExtra       = wndcls.cbWndExtra = 0;<br />
        wndcls.hInstance        = hInst;<br />
        wndcls.hIcon            = NULL;<br />
        wndcls.hCursor          = LoadCursor(NULL, IDC_ARROW);<br />
        wndcls.hbrBackground    = NULL;<br />
        wndcls.lpszMenuName     = NULL;<br />
        wndcls.lpszClassName    = "MyWndClassName";<br />
<br />
        if(!AfxRegisterClass(&wndcls))<br />
	{<br />
            AfxThrowResourceException();<br />
            return FALSE;<br />
        }<br />
    }<br />
    return TRUE;<br />
}

The function checks whether the control is registered with current resource handle, and registers it if not yet done. This way we cover both the application and DLL case. The function can be universal if you derive your custom controls from the common base class and use "MyWndClassName" as a function argument.

You may read in the MSDN what the several WNDCLASS members mean, and the code is self-commenting I guess. I hope I didn't miss anything in this explanation, but ask if there's turn out wrong. Smile | :)

Regards,
BB

Re: Custom controls in an exported DLL

DREVET Olivier7-Mar-03 1:21

DREVET Olivier

7-Mar-03 1:21

Thank you BB you're great, I'll try this as soon as possible and I'll post the result here in order to let users and you know if it works.

Thank you again !

Re: Custom controls in an exported DLL

DREVET Olivier7-Mar-03 4:34

DREVET Olivier

7-Mar-03 4:34

Dear BB,

Your solution doesn't work for the moment. After some debug, it appears that the Form View window handle is not valid. According to http://www.cpp.atfreeweb.com/MFC/LoadFrame/Index.asp[^], AfxHookWindowCreate() does the following things :
- CFrameWnd::OnCreate
- Calls CWnd::OnCreate
- Calls OnCreateClient, which, if a context with a new view class is supplied, calls CreateView (and that is where the view is created) with the context and an id of AFX_IDW_PANE_FIRST
- Sends (using PostMessage) a WM_SETMESSAGESTRING message to set the status bar message to the string with a resource id of AFX_IDS_IDLEMESSAGE
- Calls RecalcLayout

I'm sure the problem cames from CWnd::OnCreate but I don't know why it return a NULL window handle...

Re: Custom controls in an exported DLL

Bartosz Bien7-Mar-03 4:49

Bartosz Bien

7-Mar-03 4:49

When you are to create the form view, set the resource handle to the DLL one. These are the steps required (file and variable names assumed, use your own):

1. Near the DllMain function in YourDllName.cpp, find a declaration like: AFX_EXTENSION_MODULE YourDLL = { NULL, NULL };

2. In YourDllName.h (if it doesn't exist, create it), declare:
extern AFX_EXTENSION_MODULE YourDLL;

3. Before form creation, set the handle:

HINSTANCE hPrevHandle = AfxGetResourceHandle();<br />
AfxSetResourceHandle(YourDLL);

// TODO: create view here
AfxSetResourceHandle(hPrevHandle);

If the handle is not set to a module where you defined a dialog template, it cannot be loaded and thus creation fails.

Additionally, you may use a class that encapsulates above functionality and restores the original handle in its destructor (when going out of scope):

class CResourceHandler<br />
{<br />
public:<br />
    HINSTANCE m_prevHandle;<br />
<br />
public:<br />
    CResourceHandler(AFX_EXTENSION_MODULE &module);<br />
    {<br />
        m_prevHandle = AfxGetResourceHandle()<br />
        AfxSetResourceHandle(module.hModule);<br />
    }<br />
<br />
    CResourceHandler(HINSTANCE &handle)<br />
    {<br />
        m_prevHandle = AfxGetResourceHandle();<br />
        AfxSetResourceHandle(handle);<br />
    }<br />
<br />
    virtual ~CResourceHandler()<br />
    {<br />
        AfxSetResourceHandle(m_prevHandle);<br />
    }<br />
};

4. With the class, the creation code simplifies as follows:

<br />
void CreateMyFormView()<br />
{<br />
    CResourceHandler rh(YourDLL.hModule);

// TODO: create view here
}

Of course, the CreateMyFormView() function has to be located in a DLL.

Regards,
BB

Dynamic creation (instanciation) of classes

dherrero6-Mar-03 8:35

dherrero

6-Mar-03 8:35

Hi,
I have a problem. I have to read the name of a class in a data base and then try to instanciate a object of that class. How can i do it?
Example:
CString className = "CMyClass";
CRuntimeClass* ptr = RUNTIME_CLASS(class); -> Error
CObject* o = ptr->CreateObject()

Re: Dynamic creation (instanciation) of classes

Ravi Bhavnani6-Mar-03 8:37

Ravi Bhavnani

6-Mar-03 8:37

Use a class factory to instantiate the class, given its name.

/ravi

Let's put "civil" back in "civilization"
http://www.ravib.com
ravib@ravib.com

Re: Dynamic creation (instanciation) of classes

dherrero6-Mar-03 12:11

dherrero

6-Mar-03 12:11

And how do I do it?

Add about to system menu in dialog box

jimNLX6-Mar-03 8:27

jimNLX

6-Mar-03 8:27

I have a dialog application and would like to have a menu selection up in the title bar pull down menu for an "about" box. How do I add this?

My dialog has the following options selected:
Popup
Thin
title bar
system menu

Thanks for the help

Re: Add about to system menu in dialog box

Ravi Bhavnani6-Mar-03 8:35

Ravi Bhavnani

6-Mar-03 8:35

Add this code in your dialog's OnInitDialog() handler:

// Add "About..." menu item to system menu.

// IDM_ABOUTBOX must be in the system command range.
ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
ASSERT(IDM_ABOUTBOX < 0xF000);

CMenu* pSysMenu = GetSystemMenu(FALSE);
if (pSysMenu != NULL)
   {
     CString strAboutMenu;
     strAboutMenu.LoadString(IDS_ABOUTBOX);
     if (!strAboutMenu.IsEmpty())
        {
          pSysMenu->AppendMenu(MF_SEPARATOR);
          pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
        }
   }

IDM_ABOUTBOX is a string resource with the value "About MyApp..."

/ravi

Let's put "civil" back in "civilization"
http://www.ravib.com
ravib@ravib.com

Re: Add about to system menu in dialog box

jimNLX6-Mar-03 8:37

jimNLX

6-Mar-03 8:37

I just figured this was missing by doing a compare.

Now I just have to get it to call the dialog I want.

Thanks for the timely responce.

Jim

Re: Add about to system menu in dialog box

jimNLX6-Mar-03 9:12

jimNLX

6-Mar-03 9:12

Thought I had this wipped, but I can't seem to intercept the OnSystemCommand.

How does the drop down menu on the system title bar get called and where is it located?

It's like it just magically does it on its own.

Differnance between MFC extension DL L and regular mfc dll?

clintsinger6-Mar-03 8:17

clintsinger

6-Mar-03 8:17

Hi All,

I was wondering what would be the difference and why would I want to use either type. The application wizard let's me make a standard dll using mfc shared/static or an MFC extension dll.

Any clarification would be helpfull.

Cheers,
Clint

Re: Differnance between MFC extension DL L and regular mfc dll?

Bartosz Bien6-Mar-03 12:35

Bartosz Bien

6-Mar-03 12:35

http://www.codeguru.com/cpp_mfc/dill1.html

Regards,
BB

Transparent Icons

jimNLX6-Mar-03 8:17

jimNLX

6-Mar-03 8:17

I'm using CButtonST(posted there too) and am trying to make my buttons transparent, but can't seem to get it to work. Because the controls under the button are more than one color I can't just make it the same color. Is there a way I can set the icons back ground color so it doesn't display it or any other way to get around this?

Thanks

Re: Transparent Icons

DREVET Olivier7-Mar-03 3:10

DREVET Olivier

7-Mar-03 3:10

Look at the CSTButton class members, you'll find what your are searching for.

Florian

SDK & DDK

jucanpo6-Mar-03 7:58

jucanpo

6-Mar-03 7:58

Hi,
my name is Juan and I develop software since 1996 on Visual C++. Recently I try to decode the mouse protocol, so I develop a service and open one serial port and received this data, now I want to send this message from user side to kernel side, I mean, I do not want to do a driver I try to use a service. So, my problem now is how to send this information to kernel side in order to dispatch the data to the application on the user side.
I wait for any help.
Thank you so much.
Juan

Re: SDK & DDK

Chris Richardson6-Mar-03 9:35

Chris Richardson

6-Mar-03 9:35

Take a look at the mouse_event function in the MSDN.

Chris Richardson

C/C++ Include Finder[^]

Lines count

Anonymous6-Mar-03 7:49

Anonymous

6-Mar-03 7:49

Anyone got a little script how to count the lines of my RichEdit-based MDI application such as they do in HTML Editors?

Thanks

Re: Lines count

Christian Graus6-Mar-03 9:48

Christian Graus

6-Mar-03 9:48

There's a line counter add in on the site somewhere - probably the add-ins section.

Christian

NO MATTER HOW MUCH BIG IS THE WORD SIZE ,THE DATA MUCT BE TRANSPORTED INTO THE CPU. - Vinod Sharma

Anonymous wrote:
OK. I read a c++ book. Or...a bit of it anyway. I'm sick of that evil looking console window.

I think you are a good candidate for Visual Basic. - Nemanja Trifunovic

Internet protocols

Mazdak6-Mar-03 7:45

Mazdak

6-Mar-03 7:45

Can somebody tell me whats is the difference between UDP and TCP/IP protocol.I'd be sp please if you guide me to some tutorial or links about them.

Mazy

"And the carpet needs a haircut, and the spotlight looks like a prison break
And the telephone's out of cigarettes, and the balcony is on the make
And the piano has been drinking, the piano has been drinking...not me...not me-Tom Waits

Re: Internet protocols

Brian D6-Mar-03 8:27

Brian D

6-Mar-03 8:27

Quite simple really...

UDP is like fire and forget, meaning that you do not need acknowledgement of the packet getting to its destination i.e. video streaming.

TCP/IP needs to have acknowledgements meaning you are guaranteed delivery.

I do not know of any tutorials, this was from my Cisco courses.

BD

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