Re: Template parameter interpreted as base, not derived - C / C++ / MFC Discussion Boards

Re: Get text from the focused control in another window

nc3b23-Jan-09 6:14

23-Jan-09 6:14

Can you please give an example?
Suppose I have a HWND of a window (GetForegroundWindow()) and wnat to get it's focused child. How would I do that? Thank you.

Re: Get text from the focused control in another window

David Crow23-Jan-09 6:21

David Crow

23-Jan-09 6:21

First you need to get the list of processes that are running to find the one you are interested in. This can be done by calling CreateToolhelpSnapshot(), and then looping through each one with the ProcessFirst()/ProcessNext() pair. Once found, use the PID as the first argument to GetGUIThreadInfo().

"Love people and use things, not love things and use people." - Unknown

"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch

Re: Get text from the focused control in another window

nc3b23-Jan-09 6:24

nc3b

23-Jan-09 6:24

And then "hwndFocus" will contain the hwnd of the curently focused control? Thanks!

Re: Get text from the focused control in another window

Rajkumar R23-Jan-09 8:08

Rajkumar R

23-Jan-09 8:08

consider [GetWindowThreadProcessId^] also for getting the processid of the foreground window and thread id needed for GetGUIThreadInfo

Re: Get text from the focused control in another window

nc3b23-Jan-09 8:10

nc3b

23-Jan-09 8:10

Thank you!

Re: Get text from the focused control in another window

Code-o-mat23-Jan-09 6:12

Code-o-mat

23-Jan-09 6:12

I am assuming you mean getting who has the focus in a different process, so try this[^] for size.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

Template parameter interpreted as base, not derived

Member 260377223-Jan-09 4:59

Member 2603772

23-Jan-09 4:59

I have a template function to check the type passed to it. I am templatizing it on a derived type but when I break in the function, the template parameter is the base class. A sample app is below. Can someone please explain where I am going wrong?
Thanks

class Base
{
public:
	virtual ~Base() {}
};

class Derived1 : public Base {};

class Derived2 : public Base {};

template<class T> bool CheckType(boost::shared_ptr<Base> pBase)
{
	T* pTemplate = NULL;  //Why is pTemplate Base* and not Derived1* when passing a Derived1 to template parameter?
	Base* pBaseRaw = pBase.get();
	if(typeid(pBaseRaw) == typeid(pTemplate))
	{
		return true;
	}

	return false;
}

int _tmain(int argc, _TCHAR* argv[])
{
	boost::shared_ptr<Base> pBase1(new Derived1);
	boost::shared_ptr<Base> pBase2(new Derived2);
	bool bIsDerived = CheckType<Derived1>(pBase1);
	bIsDerived = CheckType<Derived2>(pBase2);

	return 0;
}

Re: Template parameter interpreted as base, not derived

Stuart Dootson23-Jan-09 6:40

Stuart Dootson

23-Jan-09 6:40

A few questions:

If I understand you correctly, CheckType is returning true, but you expected false?
What compiler (& version) are you using?

I've just tried your code with g++ 4.0.1 and it gives the results I'd expect. I added some code to print out type names:

template<class T> bool CheckType(boost::shared_ptr<Base> pBase)
{
   std::cout << typeid(T).name() << std::endl;
	T* pTemplate = NULL;  //Why is pTemplate Base* and not Derived1* when passing a Derived1 to template parameter?
	Base* pBaseRaw = pBase.get();
   std::cout << typeid(pBaseRaw).name() << std::endl;
	if(typeid(pBaseRaw) == typeid(pTemplate))
	{
		return true;
	}

	return false;
}

. I also printed out the result of CheckType and got these results:

8Derived1
P4Base
0
8Derived2
P4Base
0

So - the template parameter is Derived, the parameter is a pointer to Base, CheckType is returning false. I'm suspecting that the compiler you're using isn't fully standard compliant if it does something different?

Re: Template parameter interpreted as base, not derived

Member 260377223-Jan-09 7:12

Member 2603772

23-Jan-09 7:12

Thanks for the response. Your output is what I expected. I was looking at the pointer types in the debugger, not printing out the type info to the console. The print statements give me what you got. I am using VS2008 v9 SP1. I was performing the wrong check to get a type match. I changed the function to the following:

template<class T> bool CheckType(boost::shared_ptr<Base> pBase)
{
	Base* pBaseRaw = pBase.get();
        if(pBaseRaw == null)
        {
                return false;
        }

	if(typeid(*pBaseRaw) == typeid(T)) //Now dereferencing pBaseRaw. Bad idea?
	{
		return true;
	}

	return false;
}

I am now dereferencing the base class pointer returned from shared_ptr which casts it to the right type. I believe this is a sketchy implicit cast to the derived type. Should I just dynamic_cast or does the typeid comparison take care of type issues?

Thanks Thumbs Up | :thumbsup:

Re: Template parameter interpreted as base, not derived

Stuart Dootson23-Jan-09 8:16

Stuart Dootson

23-Jan-09 8:16

IIRC, typeid uses the same mechanism as dynamic_cast, so typeid on its own is fine.

Re: Template parameter interpreted as base, not derived [modified]

Rajkumar R23-Jan-09 7:02

Rajkumar R

23-Jan-09 7:02

Member 2603772 wrote:
T* pTemplate = NULL; //Why is pTemplate Base* and not Derived1* when passing a Derived1 to template parameter?

nope, you confused with the result, check by printing std::cout << typeid(pTemplate).name()

I think you expected the result as true and you got false (bIsDerived = true you expected, as the pointer you passed is derived).

to get what inside the pointer you can dereference it say typeid(*pBaseRaw)

so your code can be,

template<class T> bool CheckType(boost::shared_ptr<Base> pBase)
{	
	Base* pBaseRaw = pBase.get();
	<big>if(typeid(*pBaseRaw) == typeid(T))</big>	{		
		return true;	
	}	
	return false;
}

modified on Friday, January 23, 2009 1:13 PM

Re: Template parameter interpreted as base, not derived

Member 260377223-Jan-09 7:14

Member 2603772

23-Jan-09 7:14

Thanks. I just posted a similar result based on the previous response. I appreciate the help. Thumbs Up | :thumbsup:

CMFCMenuBar menu manipulation problem.

oleg6323-Jan-09 4:39

oleg63

23-Jan-09 4:39

I've started moving an MFC application to VS2008 MFC Feature Pack and got some problem with MainFrame menu manipulation.
Now the menu class is CMFCMenuBar is derived from CMFCToolbar and not rely anymore on CMenu. Seems I need to rewrite whole menu manipulation chunk the new way.
I didn't found any example of dynamic menu manipulation in Internet(like former: RemoveMenu, GetSubMenu, InsertMenu, GetSubMenu, AppendMenu, ModifyMenu, etc.)

- Is there any web resources/solutions on CMFCMenuBar dynamic menu manipulations?

Appreciate any suggestions.

Thanks.

Re: CMFCMenuBar menu manipulation problem.

Shashikant_200612-Feb-09 23:53

Shashikant_2006

12-Feb-09 23:53

use CMenu* pMenu = CMenu::FromHandle(mBar->GetHMenu());

where mBar is your CMFCMenuBar, now you can apply all the CMenu function on pMenu .

Never complain,never explain,just do your work.

Re: CMFCMenuBar menu manipulation problem.

oleg6326-Feb-09 5:33

oleg63

26-Feb-09 5:33

Thanks, it works on pop-up menus, but don't work for top level menu.

Re: CMFCMenuBar menu manipulation problem.

neuroscript30-Jan-10 13:18

neuroscript

30-Jan-10 13:18

The problem is a "glitch" (that's how I refer to it) in BCG's design of these extensions. The correct code is below (an example for removing an item), but be sure to look below the code for the important part. NOTE: "n" = your sub menu and "ID" = the ID of the menu item you want to remove.

CMenu* pMenu = CMenu::FromHandle( m_wndMenuBar.GetHMenu() );
CMenu* pSubMenu = pMenu ? pMenu->GetSubMenu( 0 ) : NULL;
if( pSubMenu ) pSubMenu->RemoveMenu( ID, MF_BYCOMMAND );

IMPORTANT (see below, too): You must FIRST go to the registry and DELETE the entry for you product. HKCU/Software/Your Product. You can just delete the correct folder for the menu, but that's up to you to figure out which one it is.

PROBLEM: This will solve it for you and new users of your product. However, existing users will never see the changes. There is a function CWinAppEx::CleanState(), which is supposed to remove memory from the registry. But, you will then have an app with no memory of toolbars, menus, etc...meaning customization is pointless.

Good luck!

File>New. Window Resizes?

theAce8923-Jan-09 4:16

theAce89

23-Jan-09 4:16

Hi all.

In my SDI application, the window frame shrinks everytime i click FILE>NEW.
My application starts maximized(SW_MAXIMIZE instead of SW_SHOW in InitInstance() of the App Class)

Anyway, as soon a click file>new, the window shrinks a bit and still shows as maximized.
My application has a splitter window, i dont know if that got to do anything this.

I am kinda new to C++ and MFC. appreciate your help.

Regards

Re: File>New. Window Resizes?

Randor 23-Jan-09 7:04

Randor

23-Jan-09 7:04

theAce89 wrote:

Anyway, as soon a click file>new, the window shrinks a bit and still shows as maximized.
My application has a splitter window, i dont know if that got to do anything this.

That is strange... it could be a number of things. The best thing to do is use the debugger to locate the responsible class. Here is how I would go about it:

1.) Locate your IDE path: (example) C:\Program Files\Microsoft Visual Studio 9.0\VC\atlmfc\src\mfc
2.) Open the core MFC file 'winocc.cpp' in your IDE.
3.) Run a Debug build of your project.
4.) Set a breakpoint on CWnd::MoveWindow and click File->New.

You may also want to check if CWnd::OnNcCalcSize or CWnd::SetWindowPos is the culprit, there are a few ways to move a CWnd derived window.

Best Wishes,
-David Delaune

Re: File>New. Window Resizes?

theAce8929-Jan-09 11:07

theAce89

29-Jan-09 11:07

Thanks David.
The culprit was actually my fault... i used the following code in the OnInitInstance() of the view classes:

CFormView::OnInitialUpdate();
GetParentFrame()->RecalcLayout();
ResizeParentToFit();

regards.

Get List of applications only

vikrant kpr23-Jan-09 1:19

vikrant kpr

23-Jan-09 1:19

Hey Friends

I am looking to get a list of applications running, or to be more specific i need main window handle only as task manager displays.

Tried EnumWinndows, but it gives many many windows, which i do not want

Many Window(s) have parent Window as 0

Looks like EnumWindows is correct way

Need Help.

Regards

Re: Get List of applications only

Nishad S23-Jan-09 1:49

Nishad S

23-Jan-09 1:49

In addition to that you should check the window styles. That is you can avoid the invisible windows, child windows, etc.

- ns ami -

Re: Get List of applications only

Sarath C23-Jan-09 1:57

Sarath C

23-Jan-09 1:57

Check this[^]

-Sarath.
"Great hopes make everything great possible" - Benjamin Franklin

My blog - Sharing My Thoughts

How to change size of dialog box @ run time?

sam_psycho23-Jan-09 0:50

sam_psycho

23-Jan-09 0:50

Hi experts,
How I can change length of dialog box at run time?
Smile | :)

Re: How to change size of dialog box @ run time?

Code-o-mat23-Jan-09 0:52

Code-o-mat

23-Jan-09 0:52

CWnd::SetWindowPos[^] to the rescue.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

Re: How to change size of dialog box @ run time?

Cedric Moonen23-Jan-09 0:54

Cedric Moonen

23-Jan-09 0:54

They hide that in the documentation: CWnd::MoveWindow[^]

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

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