Accessing Activex control methods from static functions??

[vanip]

Hi all, I am using an activex control which is registered under regsvr32. I created an MFC-dialog based aplication.I added activex control to the dialog box. And created a member-variable for the activex control thru class wizard.The member variable is m_myportcontroller.I called the activex method from a non-static member function of the dialog box using the member-variable as follows and worked fine. ex:- void CSampleDlg::process(void) { m_myportcontroller.Close(); } But i need to call the portcontroller methods from a static member function of a dialog based application (MFC). ex:- static void CSampleDlg::process(void) { m_myporcontroller.Close(); // Not accessible because static function } Please send sample code of how to access the methods from static function. Very urgently needed.Early reply is appreciatable. Awaiting for the reply, I had a problem in accessing Activex control methods from a static function

[Nibu babu thomas]

vanip wrote:

But i need to call the portcontroller methods from a static member function of a dialog based application (MFC). ex:- static void CSampleDlg::process(void) { m_myporcontroller.Close(); // Not accessible because static function }

You have to create an instance of portcontroller inside the static method. That is how static methods work since they are not instance methods but class methods. For eg:

static void CSampleDlg::process(void)
{
portcontroller pc;
pc.Close(); // now accessible
}

or

static void CSampleDlg::process(portcontroller& pc)
{
pc.Close(); // now accessible
}

vanip wrote:

Please send sample code of how to access the methods from static function. Very urgently needed.

No. :)

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Nibu thomas Software Developer

[Vinaya]

Static member functions do not have the this pointer. So they cannot access nonstatic class member data. In your case m_myportcontroller is declared as a non static data member. Vini

[vanip]

Thanks vinaya, How to make that static? I tried keeping static keyword in front of CPortController m_myportcontroller. But i am getting linker error. Do you know how to make that member as static??

[vanip]

Thanks nibu thomas, I tried this way. But getting run time assertion error. Any other way??

[Vinaya]

Static member data need to be defined outside the class declaration. You can declare the CPortController member variable as static. static CPortController m_myportcontroller ; In the CSampleDlg cpp file, define the static variable as

CPortController CSampleDlg::m_myportcontroller;

Vini

[Roger Stoltz]

Why does the function have to be static? Some kind of callback? A lot of callbacks takes a LPVOID parameter which can be used to provide the this-pointer and in the static member function type cast it so that it's possible to access non-static member variables and functions. -- Roger

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It's supposed to be hard, otherwise anybody could do it!

[vanip]

Thanks Vini, i implemented , but getting comple errors. Can u specify in more detail???? please!!!

[vanip]

Thanks Roger, The function is to be static because, i am calling this process function in a thread. How to pass the LPVOID parameter to this process function??

[Roger Stoltz]

The thread controlling function can be a non-static member of the class. When you spawn the new thread with e.g. AfxbeginThread, you should pass the this-pointer as the LPVOID parameter. Your thread controlling function takes a LPVOID as argument which would now be your this-pointer. Type cast it and you'll be able to access both non-static member variables and functions from your thread. Joe Newcomer has written a very nice article about threading that I strongly recommend everyone who is doing multithreading. You'll find it here[^]. He's got a lot of very useful tips, tricks and how-to's on his site. When you're done with the threading stuff, a new problem may occur depending on how your ActiveX works. If you plan to use COM objects from a thread you have to initialize COM for that thread by a call to ::CoInitialize or similar. This sets up a new apartment. Now you have another problem: you can't cross apartment boundaries without marshalling the COM interface. Have a look at ::CoMarshalInterThreadInterfaceInStream and ::CoGetInterfaceAndReleaseStream for info about how to do that. This is the correct way to do this. You have to marshal the interface. There are no shortcuts. Post again if you have more troubles. If they are COM/ActiveX related, post your query in the COM forum. Hope this helps -- Roger

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It's supposed to be hard, otherwise anybody could do it!

[Vinaya]

What are the compile errors you are getting? Specify the exact error messages, if possible. Vini