C / C++ / MFC

Re: How to increate network transfer speed?

24-Aug-11 21:55

Assume your program can,Then, why others program can not?
If all the programs can, what will be the result?

Charles Oppermann26-Aug-11 10:40

Charles Oppermann

26-Aug-11 10:40

So your application is more important than any other and you should be given priority?

Consider using QoS services[^]

/* Charles Oppermann */
http://weblogs.asp.net/chuckop

CFormView control sizing

Manmohan2924-Aug-11 21:33

Re: CFormView control sizing [modified]

24-Aug-11 21:33

I have two views ( CMainView and CMembersView ) in my SDI application. The code below resizes my MFC GridCtrl according to size of app's window when the view is initialized.
I get valid values for CRect grid_rect {top=0 bottom=952 left=0 right=1819} in CMainView. But in CMemberView I am having some undesired values.

C++

void CMembersView::OnInitialUpdate()
{
	
	CFormView::OnInitialUpdate();
	
	
	initialized = TRUE;

	CWnd *pGridCtrl = this->GetDlgItem(IDC_MEMBERSGRID);
	ASSERT(pGridCtrl);		// Must exist

	CRect rect,grid_rect;

	CWnd *pWnd = this->GetOwner();
	pWnd->GetClientRect(rect);
	

	pGridCtrl->GetWindowRect(grid_rect); // problem is here. no grid_rect coordinates
// grid_rect	{top=-32639 bottom=-32483 left=-32709 right=-31884}	CRect

// some adjustments
	grid_rect = rect;
	grid_rect.left += 16;
	grid_rect.top += 150;
	grid_rect.bottom -= 300;
	grid_rect.right -= 16;

	pGridCtrl->MoveWindow(grid_rect);

Where am I going wrong ?

Future Lies in Present.
Manmohan Bishnoi

xrg_soft@163.com24-Aug-11 21:52

24-Aug-11 21:52

The window size is never specified when you first call pGridCtrl->GetWindowRect(grid_rect); in the OnInitialUpdate.

Please write some codelike below in your CMembersView::OnSize

C++

CWnd *pGridCtrl = this->GetDlgItem(IDC_MEMBERSGRID);
ASSERT(pGridCtrl);		// Must exist
if ( ::IsWindow(pGridCtrl->GetSafeHwnd()) )
{
    pGridCtrl->MoveWindow(..<the_desired_size_of_gridctrl_in_the_CMembersView)
}

modified on Thursday, August 25, 2011 4:08 AM

Manmohan2924-Aug-11 22:33

Re: CFormView control sizing [modified]

24-Aug-11 22:33

Doesn't help much.

---------------------------------------------
" Future Lies in Present "_{Manmohan Bishnoi}

xrg_soft@163.com25-Aug-11 4:10

25-Aug-11 4:10

I guess you do not catch all my meaning.

If you just set the grid position in OnInitialUpdate, then even it works. There still some problem after you resize your application.

To make sure it works in all case, you must do it inside OnSize

C++

CMembersView::OnSize:
CWnd *pGridCtrl = this->GetDlgItem(IDC_MEMBERSGRID);
ASSERT(pGridCtrl);		// Must exist
if ( ::IsWindow(pGridCtrl->GetSafeHwnd()) )
{
    // assume you need to move the grid to the left half of CMembersView
    CRect rctClient;
    this->GetClientRect(&rctClient);
    pGridCtrl->MoveWindow(0, 0, rctClient.Width()/2, rctClient.Height());
}

modified on Thursday, August 25, 2011 10:19 AM

Manmohan2925-Aug-11 19:42

25-Aug-11 19:42

yes you were right. now code is working.
thanks. Thumbs Up | :thumbsup:

---------------------------------------------
" Future Lies in Present "_{Manmohan Bishnoi}

Rage24-Aug-11 22:17

24-Aug-11 22:17

IIRC GetXXXRect take pointers as parameters. Have you tried with

pGridCtrl->GetWindowRect(&grid_rect);

Same comment for the GetClientRect call a few line above.

Manmohan2924-Aug-11 22:31

24-Aug-11 22:31

This is working fine :-

C++

void CMainView::OnInitialUpdate()                  // CMainView is my application's default view
{
	CFormView::OnInitialUpdate();
	
	initialized = TRUE;
	CWnd *pGridCtrl = GetDlgItem(IDC_SALEPURCHASEGRIDCTRL);
	CRect rect,grid_rect;
	
	CWnd *pWnd = this->GetOwner();
	pWnd->GetClientRect(rect);
	

	pGridCtrl->GetWindowRect(grid_rect);     // works fine here
	grid_rect = rect;
	grid_rect.left += 16;
	grid_rect.top += 150;
	grid_rect.bottom -= 300;
	grid_rect.right -= 16;

	pGridCtrl->MoveWindow(grid_rect);        // GridCtrl is resized properly
.
.
.

This is not working properly:-

C++

void CMembersView::OnInitialUpdate()
{
	
	CFormView::OnInitialUpdate();
	
	initialized = TRUE;
	CWnd *pGridCtrl = this->GetDlgItem(IDC_MEMBERSGRID);
	ASSERT(pGridCtrl);		// Must exist

	CRect rect,grid_rect;
	
	CWnd *pWnd = this->GetOwner();
	pWnd->GetClientRect(rect);                // Also tried with &rect
	
	pGridCtrl->GetWindowRect(grid_rect); // problem is here. no grid_rect coordinates.   Also tried with &grid_rect
	grid_rect = rect;
	grid_rect.left += 16;
	grid_rect.top += 150;
	grid_rect.bottom -= 300;
	grid_rect.right -= 16;

	pGridCtrl->MoveWindow(&grid_rect);
.
.
.

---------------------------------------------
" Future Lies in Present "_{Manmohan Bishnoi}

Rage24-Aug-11 23:31

24-Aug-11 23:31

Are the coordinate that should be returned by GetWindowRect really null ? What does the debugger says (if you look into the pGridCtrl structure) ? Have tried GetLastError ?

Manmohan2924-Aug-11 23:33

24-Aug-11 23:33

In CMainView :-

grid_rect {top=-0 bottom=912 left=0 right=1819} CRect

In CMembersView :-

grid_rect {top=-32639 bottom=-32483 left=-32709 right=-31884} CRect

---------------------------------------------
" Future Lies in Present "_{Manmohan Bishnoi}

Rage24-Aug-11 23:39

24-Aug-11 23:39

Actually, you are overwriting grid_rect in the next part of the code with the content of rect, making the GetWindowRect call unnecessary. What if you comment out this line pGridCtrl->GetWindowRect(grid_rect); ?
( just to test if the MoveWindow is accepted).

Manmohan2925-Aug-11 0:05

25-Aug-11 0:05

I use it to just test whether grid_rect fetches some values or not.
Ok. I comment it out. But still it doesn't help.

---------------------------------------------
" Future Lies in Present "_{Manmohan Bishnoi}

Rage25-Aug-11 0:11

Ambiguity of 'this' and 'member function' [modified]

25-Aug-11 0:11

Then I guess the OP was right and the structure/window is not initialized properly at this point of time. So either this is the standard behaviour, and you will have to initialize it in another event, or something goes wrong when creating the GridCtrl.

Dean Seo24-Aug-11 15:12

24-Aug-11 15:12

This code below occurs no error but the result seems a bit weird.

C++

class KBase
{
public:
	void BaseFun()
	{
		printf( "KBase::BaseFun() this=%p\n", this );
	}
};

class KMiddle : public KBase
{
};

class KMiddle2 : public KBase
{
};

class KDerived : public KMiddle, public KMiddle2
{
};

int main()
{
	KDerived    d;

	d.KBase::BaseFun();   // 0012FF63
	d.KMiddle::BaseFun();  // 0012FF63
	d.KMiddle2::BaseFun();  // 0012FF64 ??

	return 0;
}//main()

BaseFun simply shows this pointer and the result goes..
---------------------------
KBase::BaseFun() this=0012FF63
KBase::BaseFun() this=0012FF63
KBase::BaseFun() this=0012FF64
---------------------------

So my question is why KBase::BaseFun() and KMiddle::BaseFun() show the same address and the only KMiddle2::BaseFun() does the different address?

I was looking for the answer by reading Stephen Prata's book and Effective C++ but I couldn't.

Thanks in advance.

modified on Wednesday, August 24, 2011 9:51 PM

xrg_soft@163.com24-Aug-11 19:32

24-Aug-11 19:32

Which complier do you use?
in some complier that follow the standard c++ strictly, like g++, your code will not compiled and got Error Message:
`D' is an ambiguous base of `B'

To make the multiple inheritance follows the standard c++ well, you should using virtual inheritance in this case.

C++

class KMiddle : virtual public KBase
class KMiddle2 : virtual public KBase

class KDerived : public KMiddle, public KMiddle2

Dean Seo24-Aug-11 20:53

24-Aug-11 20:53

Hi,

xrg_soft@163.com wrote:
Which complier do you use?

I use Visual Studio 2008.

xrg_soft@163.com wrote:
To make the multiple inheritance follows the standard c++ well, you should using virtual inheritance

I know that the multiple inheritance needs virtual inheritance.
However, when I don't on purpose, the result seems not understandable.

Could you explain to me why those 'this' addresses look unrestrained?

xrg_soft@163.com24-Aug-11 21:42

24-Aug-11 21:42

In your case(no virtual inheritance used),

the

The inside of the KDrived object, there is a KMiddle object followed by a KMiddle2 object.

d.KBase::BaseFun();
d.KMiddle::BaseFun();
actually calls to the function of the KMiddle object.

and
d.KMiddle2::BaseFun();
calls to the function of the KMiddle2 object.

As your Kxxx object contains nothing, so sizeof(Kxxx) == 1

That's why the result printed.

And if you adding somemember variable into the class, then the result should be:

KBase::BaseFun() this=<base />
KBase::BaseFun() this=<base />
KBase::BaseFun() this=<base> + sizeof(KMiddle)

Dean Seo24-Aug-11 22:36

24-Aug-11 22:36

Thank you so much!!

I truly appreciate it!

CPallini24-Aug-11 21:34

CPallini

24-Aug-11 21:34

From "Diamond problem" at Wikipedia[^]:

C++ by default follows each inheritance path separately, so a D object would actually contain two separate A objects, and uses of A's members have to be properly qualified. If the inheritance from A to B and the inheritance from A to C are both marked "virtual" (for example, "class B : virtual public A"), C++ takes special care to only create one A object, and uses of A's members work correctly. If virtual inheritance and nonvirtual inheritance are mixed, there is a single virtual A and a nonvirtual A for each nonvirtual inheritance path to A. Please note that nonvirtual derivation of A in this case will be useless as direct access to any part of class A from class D will practically always end up with compile error.

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Dean Seo24-Aug-11 22:37