C / C++ / MFC

Deriving my own base dialog

18-Apr-03 23:19

It tells the compiler to only process the header file once.

Software is everything. It also sucks. Charles Fishman [^]

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Re: pragma once

peterchen19-Apr-03 0:25

peterchen

19-Apr-03 0:25

As Taka said, it tells the compiler to process the header file only once
(unlike the usual #ifndef _HEADERNAME #define _HEADERNAME ..., it doesn't need to open the file again, start parsing etc.)

It's implemented only in certain compiler versions, for which is the additional #ifdef _MSC_VER check

"Der Geist des Kriegers ist erwacht / Ich hab die Macht" StS

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socceroli18-Apr-03 22:54

socceroli

18-Apr-03 22:54

I want to use my own dialog as a base for another one. Don't want to copy anything from the base dialog, just construct it and ready.
Someone confuses me by advising I have to add/change a constructor. I tried his way (adding UINT nId) as good as I've understood him. But seems to be not good enough. I think I'm making mistakes with the dialog id. I was told to remove the "enum {IDD...}" line. I don't understand.
What do I have to do in my base dialog and what in the derivated dialog (.h + .cpp)?

This is my code which does NOT construct the derivated dialog:

***MyBaseDlg.h***
// Two constructors
CMyBaseDlg (CWnd* pParent = NULL); // Not used by the derivated Dialog
CMyBaseDlg (UINT nIDTemplate, CWnd* pParent = NULL); // Use this one

*** MyBaseDlg.cpp***
CMyBaseDlg:: CMyBaseDlg (CWnd* pParent /*=NULL*/)
: CDialog(CMyBaseDlg::IDD, pParent)
{
}

CMyBaseDlg:: CMyBaseDlg (UINT nIDTemplate, CWnd* pParent /*=NULL*/)
: CDialog(nIDTemplate, pParent)
{
}

Derivated Dialog: class CSecondDlg : public CMyBaseDlg

***SecondDlg.h***
CSecondDlg(UINT nID, CWnd* pParent = NULL);

***SecondDlg.cpp***
CSecondDlg:: CSecondDlg (UINT nIDD, CWnd* pParent /*=NULL*/)
: CMyBaseDlg (nIDD, pParent)
{
}

Call the derivated dialog somewhere in my code:
CSecondDlg dlg(CMyBaseDlg::IDD); // How to call correctly?

Thanks,
OMG | :OMG:

Oli

Re: Deriving my own base dialog

Bartosz Bien19-Apr-03 1:43

Bartosz Bien

19-Apr-03 1:43

Here it goes:

CMyBaseDialog::CMyBaseDialog(UINT IDD, CWnd* pParent /*=NULL*/)<br />
 : CDialog(IDD, pParent)<br />
{<br />
}<br />
<br />
CSecondDlg::CSecondDlg(CWnd* pParent /*=NULL*/)<br />
 : CMyBaseDialog(CSecondDlg::IDD, pParent)<br />
{<br />
}<br />
<br />
CSecondDlg dlg;

Naturally, the "embedded" IDD should only be contained in CSecondDlg (it is not absolutely required, but helpful for ClassWizardry and such stuff).

Regards,
BB

GetDecryptionExponent in Crypto++

DREVET Olivier18-Apr-03 22:52

DREVET Olivier

18-Apr-03 22:52

Hi,

How can I use the GetDecryptionExponent function with RSAES_OAEP_SHA_Decryptor ?

This is really important for me, thank you Smile | :)

Re: GetDecryptionExponent in Crypto++

Neville Franks19-Apr-03 1:33

Neville Franks

19-Apr-03 1:33

You are more likely to get help on Crypto++ by posting to their mailing list.

Neville Franks, Author of ED for Windows. www.getsoft.com
Make money with our new Affilate program

who can answer my question?

liuty200618-Apr-03 22:45

liuty2006

18-Apr-03 22:45

the qusetion is at:
http://www.codeproject.com/listctrl/xlistctrl.asp?forumid=3227&fr=101&select=478331&df=100#xx478331xx

problem with a ToolBar

cleathley@iinet18-Apr-03 20:21

cleathley@iinet

18-Apr-03 20:21

Hi All.

I am having with a toolbar rendering it'self when its created. It doesn't display the buttons except when I run my mouse over them. they all work as far as letting the application know its working..

here is the code I am using.. as you can see Its all in win32..

Hope somebody can help.. I can supply more code if needed..

Cheers

Chris

void JumpmanEditor::CreateSideBar()<br />
{<br />
	RECT rc;<br />
	GetWindowRect(m_hWnd, &rc);<br />
<br />
	m_hWndTopBar = ::CreateWindowEx(0,<br />
									 "JumpmanStaticChild",<br />
									 "",<br />
									 WS_VISIBLE | WS_CHILD,<br />
									 0,									// x<br />
									 0,									// y<br />
									 rc.right - rc.left,				// width<br />
									 TOOLBAR_HEIGHT,					// height<br />
									 m_hWnd,<br />
									 NULL,								// menu<br />
									 g_hInst,<br />
									 0);<br />
<br />
	m_hWndTopBarScroll = ::CreateWindowEx(0,<br />
										   "JumpmanStaticChild",<br />
										   "",<br />
										   WS_VISIBLE | WS_CHILD | WS_HSCROLL,<br />
										   (TOOLBAR_BUTTON_SIZE + 2) * (TBCOUNTMAIN-1),<br />
										   0,<br />
										   rc.right - rc.left,<br />
										   TOOLBAR_PALETTE_HEIGHT + SCROLL_HEIGHT,<br />
										   m_hWndTopBar,<br />
										   NULL,<br />
										   g_hInst,<br />
										   0);<br />
<br />
	m_hWndToolbarMain = CreateToolbar((TBBUTTON *)g_tbbuttonMain, TBCOUNTMAIN, m_hWndTopBar, TOOLBAR_BUTTON_SIZE, TRUE);<br />
	m_hWndToolbarPalette = CreateToolbar((TBBUTTON *)g_tbbuttonPalette, TBCOUNTPALETTE, m_hWndTopBarScroll, TOOLBAR_PALETTE_BUTTON_SIZE, FALSE);<br />
<br />
	palettescroll = 0;<br />
	SetScrollPos(m_hWndToolbarPalette, SB_HORZ, palettescroll, TRUE);<br />
<br />
	ShowWindow(m_hWndToolbarPalette, SW_SHOWNORMAL);<br />
	ShowWindow(m_hWndToolbarMain, SW_SHOWNORMAL);<br />
}<br />
<br />
<br />
<br />
HWND JumpmanEditor::CreateToolbar(TBBUTTON *p_tbbutton, int count, HWND hwndParent, int size, BOOL text)<br />
{<br />
#define MAXRESLEN 128<br />
<br />
	int i;<br />
	HWND hwnd;<br />
<br />
	hwnd = CreateToolbarEx( hwndParent,<br />
							WS_CHILD | TBSTYLE_FLAT, // | WS_VISIBLE,<br />
							1,<br />
							count,<br />
							g_hInst,<br />
							IDB_TOOLBAR,<br />
							p_tbbutton,<br />
							count,<br />
							24,			// size of the button bitmap<br />
							24,<br />
							24,<br />
							24,<br />
							sizeof(TBBUTTON));<br />
<br />
	SendMessage(hwnd, TB_SETEXTENDEDSTYLE, 0, TBSTYLE_EX_DRAWDDARROWS);<br />
<br />
	int foo;<br />
<br />
	if (text == TRUE)<br />
	{<br />
		char szBuf[MAXRESLEN];<br />
<br />
		for (i=0;i<count;i++)<br />
		{<br />
			LoadString(g_hInst, p_tbbutton[i].dwData, szBuf, MAXRESLEN-1);<br />
			szBuf[lstrlen(szBuf) + 1] = 0;  //Double-null terminate.<br />
			foo = SendMessage(hwnd, TB_ADDSTRING, 0, (LPARAM) szBuf);<br />
		}<br />
	}<br />
<br />
	SendMessage(hwnd, TB_SETBUTTONWIDTH, 0, (LPARAM)(DWORD)MAKELONG(size,size));<br />
<br />
	for (i=0;i<count;i++)<br />
	{<br />
		TBBUTTONINFO tbbi;<br />
		tbbi.cbSize = sizeof(tbbi);<br />
		tbbi.dwMask = TBIF_SIZE | TBIF_COMMAND | TBIF_STATE | TBIF_STYLE;<br />
		foo = SendMessage(hwnd, TB_GETBUTTONINFO, p_tbbutton[i].idCommand, (LPARAM)&tbbi);<br />
		// ensure all icons are the same size<br />
//		tbbi.cx = size;<br />
		foo = SendMessage(hwnd, TB_SETBUTTONINFO, p_tbbutton[i].idCommand, (LPARAM)&tbbi);<br />
	}<br />
<br />
	SendMessage(hwnd, TB_AUTOSIZE, 0, 0);<br />
<br />
	return hwnd;<br />
	}<br />

Question about friend function.

George218-Apr-03 18:52

18-Apr-03 18:52

Hi, everyone!

I ofter heard from others that the place where to define
a friend function of a class depend on whether the
client code is supposed to call that function or not. But
in my experience I always define the friend function in
.h file. I simply want to know what means "whether the
client code is supposed to call that function or not".

Can you give me an example?

regards,
George

Homework alert!!!

Taka Muraoka18-Apr-03 19:21

18-Apr-03 19:21

Dude, you seem to hear a lot of things from others! Laugh | :laugh:

Software is everything. It also sucks. Charles Fishman [^]

Awasu 1.0.3 (beta)[^]: A free RSS reader with support for Code Project.

George218-Apr-03 19:26

18-Apr-03 19:26

Thanks, Taka buddy!

I like to hear and read experience by experienced
people. For example, programming experience. But
for a newbie, some experiences are too beief without
an example. For example, something like "10 rules of
...". So I just want to let experienced people to tell
me what they are talking about.

Smile | :)

regards,
George

Taka Muraoka18-Apr-03 19:41

18-Apr-03 19:41

No problems Smile | :)

So, where did you hear this? Friends are *always* defined in the class definition which is usually going to be in a header file.

Software is everything. It also sucks. Charles Fishman [^]

Awasu 1.0.3 (beta)[^]: A free RSS reader with support for Code Project.

George218-Apr-03 20:29

18-Apr-03 20:29

Thanks, Taka buddy!

If you have ever studied how the compiler is working,
you will see what is my trouble. Suppose functionA is defined
in a header file. The compiler will recognize functionA as
valid identifier in any translation unit that includes A.h.
The function has external linkage by default. So I think if
a function is not called by others, it will be a waste to
define the function in the header file. Define it in .cpp
file is just OK. Since compiler external linkage will make
my program larger. But I do not know whether I am correct.

Can anyone help?

regards,
George

Taka Muraoka18-Apr-03 20:35

18-Apr-03 20:35

Defining a function in a header simply tells the compiler that the function exists (somewhere else) and has the specified signature.

You need to do it so that the compiler won't flag an error when you try to use it. That's all. If you don't call that function, it won't make your EXE bigger.

Declaring it in a CPP file is *wrong* since it is easy to change the signature of the function and forget to update the other declarations. If you have it in a single place i.e. the header file, you are more likely to get it right. If you are using a C++ compiler, name-mangling means that the linker is likely to flag an error but it's still bad practice.

Software is everything. It also sucks. Charles Fishman [^]

Awasu 1.0.3 (beta)[^]: A free RSS reader with support for Code Project.

George218-Apr-03 20:43

18-Apr-03 20:43

Thanks, Taka buddy!

Your reply has answered most of my questions. Now I
have a last question, can you show me a case
where the client code is not supposed to call that
function but we must define the function in .cpp file
and better not in .h file? I can not imagine that case.

regards,
George

Nish Nishant18-Apr-03 21:46

Nish Nishant

18-Apr-03 21:46

Hello George,

Since MS introduced MC++ they've been promoting inline function definitions for classes. This renders the need for a separate header file a mere formality and thus some people actually avoid using header files.

But if you are planning on writing some global fucntions then it might be a darn good idea to keep them in a separate header file.

Regards,
Nish

Author of the romantic comedy

Summer Love and Some more Cricket [New Win]

Review by Shog⁹
Click here for review[NW]

George218-Apr-03 21:56

18-Apr-03 21:56

Thanks, Nishant buddy!

When you say inline function. Do you mean define a
function inside the .h file?

What means "This renders the need for a separate header
file a mere formality and thus some people actually
avoid using header files" in your reply? Why people avoid
using that way? Can you show me an example?

regards,
George

Nish Nishant19-Apr-03 6:34

Nish Nishant

19-Apr-03 6:34

George2 wrote:
When you say inline function

Something like :-

class Abc()
{
    void Hello()
    {
        //...
    }
};

Hello is defined directly here as you can see. If you were using separate CPP and H files you'd have put just the declration in the H file and the definition would have been in the CPP file

George2 wrote:
Can you show me an example?

Well the main CPP file for an MC++ project need not have a H file. You juyst put all your classes into this main CPP file. And similarly any other classes might be fully defined in a H file (this time no separate CPP files)

Regards,
Nish

Author of the romantic comedy

Summer Love and Some more Cricket [New Win]

Review by Shog⁹
Click here for review[NW]

George219-Apr-03 18:54

Question about type conversion operator.

19-Apr-03 18:54

Thanks, Nishant buddy!

George

George218-Apr-03 18:48

Re: Question about type conversion operator.

18-Apr-03 18:48

Hi, everyone!

I have heard that type conversion operator will
produce ambiguity when the compiler is implicitly
converting your types for you when the error will
occur "there are two or more functions that match..."
But I have not found an example code. I just heard that
but have never met with the very case.

Can you show me one example of that?

regards,
George

Michael Dunn18-Apr-03 19:47

Michael Dunn

18-Apr-03 19:47

Here's a really rough example Smile | :)

void f(int n) { }
void f(char* p) { }
 
class C
{
public:
  operator int() { return 1; }
  operator char*() { return "hi!"; }
};
 
main()
{
C obj;
 
  f(obj);  // error, ambiguous because either 
           // overload of f could apply here
}

--Mike--
THERE IS NO THERE IS NO BUT THERE IS MAGIC PIXIE DUST BUSINESS GENIE CODE PROJECT

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Re: Question about type conversion operator.

George218-Apr-03 20:25