C / C++ / MFC

30-Jun-19 5:50

Hi
IS there a way to return from DoModal without having a PUSH BUTTON with the value of IDOK ,IDCACEL or IDABORT I would like to have 3 radio buttons specifying 3 choice and return the value of one of those to DoModal

thanks

Victor Nijegorodov30-Jun-19 7:43

Victor Nijegorodov

30-Jun-19 7:43

ForNow wrote:
IS there a way to return from DoModal without having a PUSH BUTTON with the value of IDOK ,IDCACEL or IDABORT

Yes. Just press the Enter button.

Randor 30-Jun-19 8:13

Randor

30-Jun-19 8:13

Hi,

ForNow wrote:
Hi

Is there a way to return from DoModal without having a PUSH BUTTON with the value of IDOK?

Yes.

You would need to call the EndDialog function with the second argument set to the ID of your radio button. If you are not using Windows API and are using MFC instead... you would call CDialog::EndDialog

Best Wishes,
-David Delaune

ForNow30-Jun-19 8:53

30-Jun-19 8:53

I thought enddialog takes the value returned from DoModal

How can I pass return value to DoModal without one the predefined ways/values Microsoft is forcing me

I for instance would like to return the ID of a radio button which tell me which one of the options the user selected

Randor 30-Jun-19 9:08

Randor

30-Jun-19 9:08

ForNow wrote:
I thought enddialog takes the value returned from DoModal

You have that backwards... DoModal() receives the return value from EndDialog()

ForNow wrote:
How can I pass return value to DoModal without one the predefined ways/values Microsoft is forcing me

C++

EndDialog(YourWindowHandle,YOUR_RADIO_ID); //If you're using Windows API
EndDialog(YOUR_RADIO_ID); //If you're using MFC Wrapper

Best Wishes,
-David Delaune

ForNow30-Jun-19 10:43

30-Jun-19 10:43

Thanks

My DoModal is being called from
My CMainFrame once returning to DoModal via EndDialog the Dialog box is destroyed but the class/object is still around ( I created the modal Dialog on the stack ) so the data in the class is still available until I exit the CMainFrame Routine

Also the only way to have a bad return code from UpdateData is to call pDx->fail which has the side effect of an exception which I would have to delete. if everything is okay I just call EnDialog notifying the CMainFrame which called DoModal of my selection
Thanks

Randor 30-Jun-19 15:22

Randor

30-Jun-19 15:22

Hi,

I am happy to hear that you have it working. Smile | :)

ForNow wrote:
Also the only way to have a bad return code from UpdateData is to call pDx->fail which has the side effect of an exception which I would have to delete. if everything is okay I just call EndDialog notifying the CMainFrame which called DoModal of my selection

OK, let me know if you have any problems here. But from what you've described it sounds like the desired outcome.

Best Wishes,
-David Delaune

ForNow30-Jun-19 17:24

30-Jun-19 17:24

only one Issue UpdateData seems to always return TRUE even if I call pDX->fail

maybe I should set a global BOOL in my Modal Dialog Class and bypass checking return code from UpdateData

Thanks

Randor 30-Jun-19 18:34

Randor

30-Jun-19 18:34

ForNow wrote:
only one Issue UpdateData seems to always return TRUE

That means UpdateData() succeeded. Can you explain to me why you need UpdateData to fail?

ForNow wrote:
even if I call pDX->fail

With my experience I am going to make a strong inference that your pDX variable is a pointer to a CDataExchange object. Can you explain to me why you need this to fail? If this fails a runtime error will be thrown... I can't even think of a valid reason you would want this.

The source for UpdateData() is inside wincore.cpp and you will find that the UpdateData() function constructs a new CDataExchange object and attaches it to your Cwnd object and performs DDX through there.

In other words... your line of code inside your class:

C++

pDX->Fail(); // This fails because it's a pointer to another CDataExchange object.

You should to open [Your Visual Studio Path]\VC\atlmfc\src\mfc\wincore.cpp and scroll down to the Updatedata() implementation where you will immediately understand why UpdateData() always returns TRUE; It creates a new CDataExchange object inside the function. You cannot force UpdateData() to fail by manipulating an external object.

Best Wishes,
-David Delaune

Victor Nijegorodov30-Jun-19 22:37

Victor Nijegorodov

30-Jun-19 22:37

ForNow wrote:
only one Issue UpdateData seems to always return TRUE even if I call pDX->fail

maybe I should set a global BOOL in my Modal Dialog Class and bypass checking return code from UpdateData

Why do you need the "return code from UpdateData"?
Why do you need the UpdateData at all? There was a great essay about Avoid UpdateData of Joe Newcomer. I'd recommend you to check it out!

HRESULT variable returning negative value

Randor 30-Jun-19 23:38

Randor

30-Jun-19 23:38

Hi Victor,

I've been meaning to tell you that I am happy to see you have finally moved over here from CodeGuru. I followed Chris over to his new site some 18+ years ago soon after Zafir Anjum sold codeguru and I rarely go back to the old site anymore.

Victor Nijegorodov wrote:
Why do you need the UpdateData at all? There was a great essay about Avoid UpdateData of Joe Newcomer. I'd recommend you to check it out!

Actually in this case he may need to call UpdateData() because he is bypassing both the CWnd::OnOk and also exiting the dialog with EndDialog(SOME_RADIO_ID); With that knowledge go and read the final two paragraphs in the debate between Doug Harrison and Dr. Newcomer.

If we are going to suggest that the poster "ForNow" avoid using UpdateData() then we need to ensure that he is using control variables.

Best Wishes,
-David Delaune

P.S.
I haven't used MFC in nearly 10 years, not sure why I even remember these things.

Member 1449956328-Jun-19 6:58

Member 14499563

28-Jun-19 6:58

Greetings.

I'm a newbie here and also into C++ programming but I would like to say this is a very helpful site to watch and learn and I would like to thank to all you out there for sharing your knowledge.

As part of my interests about C++ and COM objects I was looking some tutorials and I have found this one nicely done:

COM from scratch - PART TWO[^]

I'm trying to re-create the client part of the improved example but it's not working. When I tried to do some debugging I was looking at some values and I've found this:

C++

hr=-2147221164

Looking for some explanation I made some research and I understood that -among other things- this might be happening because of some uninitialized pointers, but I tried that suggestion and still no luck with MSVS 2008 and this simple code for a client-server application.

C++

//-----------//
// Client
//-----------//
void main()

{
    HRESULT hr;
    IUnknown* pIUnknown;
    IComponent* pIComponent;
    IClassFactory* pIClassFactory;

    ::CoInitialize(NULL);
    /*
    //Once the CoCreateInstance is called, the component 
    //will be created and the client can not 
    //control it, that's why CoCreateInstance is inflexible 
    //and the solution is to call CoGetClassObject function
    hr = ::CoCreateInstance(CLSID_Component,NULL,
            CLSCTX_INPROC_SERVER,IID_IUnknown,(void**)&pIUnknown) ; 
    if (SUCCEEDED(hr))
        {
            hr=pIUnknown->QueryInterface(IID_IComponent,(void**)&pIComponent);
            if(SUCCEEDED(hr))
               pIComponent->Print("COM from scratch.");
        }

     */ 
    //-------------------------------//
    // improvement of the client code
    //------------------------------//
    // By calling the CoGetClassObject function, the client can control
    // creation of the component
    hr=CoGetClassObject(CLSID_Component,CLSCTX_INPROC_SERVER, 
                 NULL,IID_IClassFactory,(void**)&pIClassFactory);
    if (SUCCEEDED(hr))
    {
        hr=pIClassFactory->CreateInstance(NULL,
                IID_IComponent,(void**)&pIComponent);
        if(SUCCEEDED(hr))
           pIComponent->Print("COM from scratch.");
    }

    ::CoUninitialize ();

}

What could be the reason(s) this

C++

hr

variable is returning that value and how to fix it? Thank you in advance

jeron128-Jun-19 7:15

jeron1

28-Jun-19 7:15

Perhaps there is something useful in this[^] thread.

"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment
"Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst
"I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle

Member 1449956328-Jun-19 7:57

Member 14499563

28-Jun-19 7:57

Hey, thank you very much for that fast reply.

I saw that discussion and I see all those errors are related to a poor server registration. In my case, I double checked that my server is registered when I was doing some debugging. If you see the paths provided in the sources there is certainly something like this:

C++

REGEDIT
 HKEY_CLASSES_ROOT\Codeproject.Component.1 = 
            Codeproject Component Version 1.0
 HKEY_CLASSES_ROOT\Codeproject.Component.1\CLSID = 
            {49BF12F1-5041-48da-9B44-AA2FAA63AEFB}
 HKEY_CLASSES_ROOT\Codeproject.Component = Codeproject Component 
 HKEY_CLASSES_ROOT\Codeproject.Component\CurVer = Codeproject.Component.1
 HKEY_CLASSES_ROOT\CLSID\{49BF12F1-5041-48da-9B44-AA2FAA63AEFB} = 
            Codeproject Component 1.0
 HKEY_CLASSES_ROOT\CLSID\{49BF12F1-5041-48da-9B44-AA2FAA63AEFB}\InprocServer32 = 
            c:\codeproject\component.dll
 HKEY_CLASSES_ROOT\CLSID\{49BF12F1-5041-48da-9B44-AA2FAA63AEFB}\ProgID = 
            Codeproject.Component.1
 HKEY_CLASSES_ROOT\CLSID\{49BF12F1-5041-48da-9B44-AA2FAA63AEFB}\
            VersionIndependentProgID = Codeproject.Component

All my entries are OK with my server registered so I suppose the problem is somewhere but I can't find it because my lack of expertise. Looking at the MSDN/documentation the value expected should be one of these:

C++

S_OK
Location and connection to the specified class object was successful.

REGDB_E_CLASSNOTREG
The CLSID is not properly registered. This error can also indicate that the value you specified in dwClsContext is not in the registry.

E_NOINTERFACE
Either the object pointed to by ppv does not support the interface identified by riid, or the QueryInterface operation on the class object returned E_NOINTERFACE.

REGDB_E_READREGDB
There was an error reading the registration database.

CO_E_DLLNOTFOUND
Either the in-process DLL or handler DLL was not found (depending on the context).

CO_E_APPNOTFOUND
The executable (.exe) was not found (CLSCTX_LOCAL_SERVER only).

E_ACCESSDENIED
There was a general access failure on load.

CO_E_ERRORINDLL
There is an error in the executable image.

CO_E_APPDIDNTREG
The executable was launched, but it did not register the class object (and it may have shut down).

and not that negative value

C++

hr=-2147221164

What could be happening with this variable

C++

hr

if all variables/pointers are initialized and the server/COM Object is well registered with its CLSID for a Win32 app target?

Victor Nijegorodov28-Jun-19 8:42

Victor Nijegorodov

28-Jun-19 8:42

From MSDN:

Quote:
REGDB_E_CLASSNOTREG
0x80040154
Class not registered

Haven't you registered it?
Or did you mix something related 32/64bit?