C / C++ / MFC Discussion Boards

Re: how do you get the index of a row in a list control

Hamid_RT21-Oct-07 2:22

Hamid_RT

21-Oct-07 2:22

GetNextItem(-1,LVNI_SELECTED);.

Re: how do you get the index of a row in a list control

lgbean21-Oct-07 9:40

lgbean

21-Oct-07 9:40

GetNextItem()
retrun value is an integer.the integer is your need

What should I do?

bornunique21-Oct-07 1:33

bornunique

21-Oct-07 1:33

About several weeks I tried to learn MFC,but unfortunately failed to do so.
At first I was confident ,but then I got frustrated 、confused and didn't know what to do.
I think I've known C++ well,and know something about computer organization and operating
system .But I just could copy the same codes as described in the books,even cannot change a bit.
I didn't know exactly what the code means,and could nou find the ways.Is it googbye to the MFC world? I wonder....
Hope for help. Cry | :((

Re: What should I do?

Hamid_RT21-Oct-07 1:58

Hamid_RT

21-Oct-07 1:58

If you can not write your code so you are faint on MFC and need to more work of course codeproject has articles about MFC and its controls but I suggest see codes that has beginner on their titles, do you know c++ very well for example Object Oriented Programming (inheritance,Polymorphism) and Type Casting,Preprocessor directives, Input/Output,Arrays,Pointers Dynamic Memory and other things,but I didnt understand you cant change codes on books?

Re: What should I do?

Johpoke21-Oct-07 2:22

Johpoke

21-Oct-07 2:22

Take a look at "Teach Yourself Visual C++ 6 in 21 days" Its great, for the total beginners, and for slightly experienced. It did help me with some stuff too...

//Johannes

Re: What should I do?

Mark Salsbery21-Oct-07 7:27

Mark Salsbery

21-Oct-07 7:27

If you really want to learn MFC, then you really need to understand
Windows programming.

Start with the basics. Get the book "Programming Windows" by Charles Petzold
or an equivalent. Make sure you understand Windows Messaging, the basics of
Win32 APIs, etc.

MFC will make a lot more sense if you understand what's going on.

Just my opinion,
Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: What should I do?

Nelek21-Oct-07 20:29

Nelek

21-Oct-07 20:29

One thing I made when I started with MFC was, after reading some online manuals and articles of codeproject, started a MFC-Win32 application with the wizard of VC++ 6.0. Then, just with the 5 classes created (CMyApp, CMyDoc, CMyView, CMainFrm, CChildFrm), I used the class wizard to call almost all messages in every class. Just putting an AfxMessageBox ("(Funct Nr XX) The function XXXX is being called") and just played with the windows up and down, clicking, opening docs, closing docs, destroying windows, resizing... all what I could do with empty code.

Afterwards, when I more or less knew the order in which functions are called. I put some break points here and there. When the debug stays in a break point, you get a step towards with F10, but if you use F11, the step is towards (but going INTO the called code). I mean.

BOOL CMyApp::InitInstance ( )
{

//Some code

	if (!ProcessShellCommand(cmdInfo))      //<<<----- Break point here
		return FALSE;

	// Das Hauptfenster ist initialisiert und kann jetzt angezeigt und aktualisiert werden.
	pMainFrame->ShowWindow(m_nCmdShow | SW_SHOWMAXIMIZED);
	pMainFrame->UpdateWindow();
}

When compile, it stops at the if. If you use F10, it will go to pMainFrame->ShowWindow (...); (next line in the same layer). But if you use F11 insteads, then you will go to the next step in a deeper layer:

// This is a part of the Microsoft Foundation Classes C++ library.
// Copyright (C) 1992-1998 Microsoft Corporation
// All rights reserved.

BOOL CWinApp::ProcessShellCommand(CCommandLineInfo& rCmdInfo)
{
	BOOL bResult = TRUE;
	switch (rCmdInfo.m_nShellCommand)
	{
	case CCommandLineInfo::FileNew:
		if (!AfxGetApp()->OnCmdMsg(ID_FILE_NEW, 0, NULL, NULL))
			OnFileNew();
		if (m_pMainWnd == NULL)
			bResult = FALSE;
		break;
//more code
}

That is part of the hidden code that you don't usually see.

Maybe this is not the best way to learn it correctly, but for me was ok to have a global idea (seeing more or less how the functions are distributed and reading the comments from Microsoft in the code). And after I went deeper in contents as I needed new things.

Greetings.

--------
M.D.V.

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?

Help me to understand what I'm saying, and I'll explain it better to you

Wink | ;)

Re: What should I do?

David Crow22-Oct-07 5:16

David Crow

22-Oct-07 5:16

You're throwing in the towel only after a couple of weeks of learning MFC? Amazing! I've still not got it all figured after 15 years. Maybe I'm just stubborn.

"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

MFC focus question

FredrickNorge21-Oct-07 0:14

FredrickNorge

21-Oct-07 0:14

I have a question in regards to, if there is a built in function in mfc
i can overload that gets called when a dialog is brought back to focus
after a DoModal() operation. I end the modal dialog with OnOK().

the OnPaint() starts to paint again when its brought back to focus,
but is there is a cleaner way to check for this event?

Thanks

Re: MFC focus question

Mark Salsbery21-Oct-07 7:40

Mark Salsbery

21-Oct-07 7:40

I'm not sure what you're asking...

As soon as DoModal() returns, the modal dialog
has been dismissed. While the modal dialog was displayed,
other windows should still get WM_PAINT messages.
If you've halted painting before calling DoModal(), then just
start painting again when DoModal() returns.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: MFC focus question

FredrickNorge21-Oct-07 11:12

FredrickNorge

21-Oct-07 11:12

The initial dialog does not paint when there is
a modal dialog in focus, because i run the app in full screen.

But if there are no functions that i can use that deals
with "OnFocus", WM_PAINT works, i just need to be carefull with it.

Thanks

Fredrick

Re: MFC focus question

Stephen Hewitt21-Oct-07 19:40

Stephen Hewitt

21-Oct-07 19:40

You could use the WM_ACTIVATE[^] message. Use a handler which looks something like this:

void CDialogAppDlg::OnActivate(UINT nState, CWnd* pWndOther, BOOL bMinimized) 
{
	CDialog::OnActivate(nState, pWndOther, bMinimized);
	
	if (nState==WA_ACTIVE || nState==WA_CLICKACTIVE)
	{
		// Do stuff here!
	}
}

Steve

Re: MFC focus question

FredrickNorge21-Oct-07 21:45

FredrickNorge

21-Oct-07 21:45

Perfect, just what i needed.

Thanks!

trim heading and trailing space

George_George20-Oct-07 21:52

George_George

20-Oct-07 21:52

Hello everyone,

I think in built-in C/C++ functions, there is no direct function call to trim heading and trailing space characters, right? So, we have to implement it manually by iterating the string to check character one by one.

Support not using MFC.

thanks in advance,
George

Re: trim heading and trailing space

Christian Graus20-Oct-07 23:40

Christian Graus

20-Oct-07 23:40

http://www.codeproject.com/vcpp/stl/stdstringtrim.asp[^]

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: trim heading and trailing space

George_George21-Oct-07 3:18

George_George

21-Oct-07 3:18

Hi Christian,

It is implemented by find_first_not_of and find_last_not_of of STL string,
no built-in functions.

regards,
George

Re: trim heading and trailing space

henk21cm20-Oct-07 23:46

henk21cm

20-Oct-07 23:46

G'day George,

dBaseIII had a popular function for this purpose, alltrim. In the mid nineties i needed that function in C and wrote the following implementation, plain C code.

<br />
char    *alltrim( char *t)<br />
{<br />
        unsigned char   *t_, *tc_;<br />
        int     i=0, l;<br />
<br />
        l = strlen(t);<br />
        tc_ = (unsigned char*) t;<br />
/*      Remove all spaces before any usefull characters */<br />
<br />
        while (*(tc_+i) <= ' ' && i < l)<br />
                i++;<br />
<br />
        if (i==l)       /* Everything is white space   */<br />
                {<br />
                *t = (char) 0;  /* return an empty string       */<br />
                return t;<br />
                }<br />
        else<br />
                t_ = ( unsigned char* ) (t+i);  /* t_ points to the first non-whitespace        */<br />
<br />
/*              Process the rear end of the string */<br />
<br />
        i=l-1;<br />
        while (*(tc_+i) <= ' ')<br />
                i--;<br />
        i++;                    /* Index of the 1st whitespace at the rear end of the text      */<br />
        *(t+i) = ( char ) 0;                            /* change into ASCIIZ   */<br />
        l = strlen((char*) t_) + 1;                     /* Length clean  string + ASCIIz        */<br />
        memmove(t, t_, l);                              /* Secure even when overlapping */<br />
        return t;<br />
}<br />

Unfortunatedly the preview of the code looks awfull, like it has been handled by alltrim itself.

Regards,
Henk

21cm: the universal wavelength of neutral hydrogen

Re: trim heading and trailing space

George_George21-Oct-07 3:16

George_George

21-Oct-07 3:16

Thanks Henk,

I think you mean there is no built-in function.

regards,
George

File read problem

pri_skit20-Oct-07 20:05

pri_skit

20-Oct-07 20:05

I have written a CString Object into Text file by using :
f.Write (&FileName,FileName.GetLength());//FileName is CString Object

Now I want to Read CString object back How this could be done?I am using code :

LPTSTR p = CurrentLanguageName.GetBuffer(11);
void *g=(void *)p;
f.Read (g,CurrentLanguageFileLen);
CurrentLanguageName.ReleaseBuffer( );
//But this method don't work.

Regards,

priyank

Re: File read problem

karle20-Oct-07 21:36

karle

20-Oct-07 21:36

you better use CStdioFile class which is derived from CFile.
It has a ReadString and a WriteString method.

Re: File read problem

KEL322-Oct-07 1:49

KEL3

22-Oct-07 1:49

Try the following to write:
CString StringToWrite;
StringToWrite="ABC";//e.g.
f.Write (StringToWrite.GetBuffer(20),StringToWrite.GetLength()+1);

Try the following to read:

CString str;
char B;
for(i=0;i<1000;i++){
f.Read(&B,sizeof(B));
str+=B;
if(B=='\0')break;
}

Not the best way to do it, but if it work U R OK!

kostas KEL

Re: File read problem

David Crow22-Oct-07 5:25

David Crow

22-Oct-07 5:25

KEL3 wrote:
f.Write (StringToWrite.GetBuffer(20),StringToWrite.GetLength()+1);

Why are you unnecessarily calling GetBuffer()?

Re: File read problem

David Crow22-Oct-07 5:28

David Crow

22-Oct-07 5:28

pri_skit wrote:
f.Write (&FileName,FileName.GetLength());//FileName is CString Object

You might want to check the contents of the file you are writing to, as you are writing the address of the CString object to the file.

pri_skit wrote:
//But this method don't work.

Why are you bothering with a void pointer?

Re: File read problem

KEL322-Oct-07 22:00

KEL3

22-Oct-07 22:00

DavidCrow wrote:
Why are you unnecessarily calling GetBuffer()?

If you write:
f.Write (&FileName,FileName.GetLength());
you are about to write the whole object into the file
(including private variables etc...) and that is generally
BAD.
In fact the correct code for that would be:
f.Write (&FileName,sizeof(FileName));
since the previous code would probably crash your app
if the string buffer (allocated on the heap) is longer
than the size of the object.

===============================================

A little correction:
Try the following to read:

CString str;
char B;
for(i=0;i<1000;i++){
f.Read(&B,sizeof(B));
if(B=='\0')break; // Before "str+=B;" to avoid adding two '\0' at the end.
str+=B;
}

kostas KEL

Re: File read problem

David Crow23-Oct-07 2:53

David Crow

23-Oct-07 2:53

KEL3 wrote:
In fact the correct code for that would be:
f.Write (&FileName,sizeof(FileName));

Wrong. This would still write the address of FileName to the file. Why is it so hard to code something like:

f.Write(FileName, FileName.GetLength());

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