C / C++ / MFC Discussion Boards

Abhijeet Pathak31-Aug-07 21:46

31-Aug-07 21:46

I've a MFC dialog with two edit boxes...
By default focus in on first text box.
I want that during dialog load if first edit box contains some text,
then second edit box should have focus... I've tried SetFocus() in InitDialog()
but it's not working... focus still remains on first control.

How should I do it? Please Help!

Re: Focus Problem

chandu00431-Aug-07 21:49

chandu004

31-Aug-07 21:49

make sure that Set focus() is the last statement in the init dialog.
if it is so,
just post a sample of your init dialog code, i shall solve it

Re: Focus Problem

Nishad S1-Sep-07 2:18

Nishad S

1-Sep-07 2:18

You have to return FALSE from OnInitDialog if you need to set the focus to a particular control by yourself.

- NS -

Re: Focus Problem

Mark Salsbery1-Sep-07 7:48

Mark Salsbery

1-Sep-07 7:48

In addition to what NS17 stated, you should also use GotoDlgCtrl() instead of SetFocus()
when setting the focus to edit controls.

Mark

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

Re: Focus Problem

Gary R. Wheeler2-Sep-07 14:30

Gary R. Wheeler

2-Sep-07 14:30

If you change the focus in OnInitDialog() to something other than the first control, make sure that your OnInitDialog() handler returns FALSE. If it returns TRUE, the default Window handler sets the focus for you, overriding anything you did.

Software Zen: delete this;

Fold With Us![^]

Suggestion to members [modified]

chandu00431-Aug-07 21:46

chandu004

31-Aug-07 21:46

i advice all the members who are starting the threads to indicate a keyword like [SOLVED] by prefixing the same to the main subject, once they are solved
thanks.

-- modified at 3:59 Saturday 1st September, 2007

Indicate the prefix [SOLVED] in the subject when solved

Russell^'31-Aug-07 22:13

Russell^'

31-Aug-07 22:13

Put that advice directly as 'Subject' like mine.
It will be more visible

Big Grin | :-D

Russell

Re: Indicate the prefix [SOLVED] in the subject when solved

chandu00431-Aug-07 22:20

chandu004

31-Aug-07 22:20

thanks russel,
but can you suggest me some idea such that it always sits on top of all the posts. like that of chris maunder.

Re: Indicate the prefix [SOLVED] in the subject when solved

Russell^'31-Aug-07 22:41

Russell^'

31-Aug-07 22:41

To suggestions forum -> [^]
Big Grin | :-D

Russell

Re: Suggestion to members

Hamid_RT1-Sep-07 1:01

Hamid_RT

1-Sep-07 1:01

Wow I said what happend you used of B tags;) its good idea.;)

why 2 vfptrs in case of virtual inheritance?

Sameer_Thakur31-Aug-07 19:58

Sameer_Thakur

31-Aug-07 19:58

Hi all.
Here are the two classes one base and other Derived ( virtually inherited from Base)

Class Base
{
Public:
Virtual void FunB(){}
};

Class Derived: virtual public Base
{
Public:
Virtual void FunD(){}
};

When I derived class Derived virtually from Base, and when I saw the memory layout of objects of Derived in debug window; I saw two separate vfptrs; one for Base and one for Derived.
But if I do not derive class Derived virtually from Base, then there is only single vfptr in object of Derived class?
Why an extra vfptr is added/required in case of virtual inheritance?

Sameer Thakur

Re: why 2 vfptrs in case of virtual inheritance?

Gary R. Wheeler2-Sep-07 4:36

Gary R. Wheeler

2-Sep-07 4:36

Try reading this article[^] in the C++ FAQ, especially section 25.9 on virtual inheritance.

Software Zen: delete this;

Fold With Us![^]

convert path to HTREEITEM [modified]

revanth198531-Aug-07 19:08

revanth1985

31-Aug-07 19:08

Hi,
How can find handle to the treeitem if i know its path in a tree control.

-- modified at 4:33 Saturday 1st September, 2007

Re: path to HTREEITEM

Hamid_RT31-Aug-07 21:27

Hamid_RT

31-Aug-07 21:27

See GetNextItem(handle to item on the tree,here flags you can use for example TVGN_CHILD

Re: path to HTREEITEM

revanth198531-Aug-07 22:27

revanth1985

31-Aug-07 22:27

Thanks,but i don't have any handle.I have only path(for ex: A\Apple\fruit).What i need is handle to the tree item "fruit".How to get it.

Re: path to HTREEITEM

Hamid_RT1-Sep-07 0:56

Hamid_RT

1-Sep-07 0:56

Here some function on the CTree class that you can use of them for get handle to root GetRootItem and GetParentItem. but I think you are new to this section so I suggest see articles on the codeproject about CTree.

Re: convert path to HTREEITEM

Gary R. Wheeler2-Sep-07 4:42

Gary R. Wheeler

2-Sep-07 4:42

You have to use the GetRootItem() and GetNextItem()[^] member functions in the CTreeCtrl class to traverse the nodes in the tree. Use the GetItem() function to retrieve information about each node, including the node's text. Compare the node's text to that part of the 'path'.

For example, if the path is C:\Forest\Orchard\Apple, start at the root and look for the node with the text 'Forest'. Within the nodes attached to the 'Forest' node, look for one with the text 'Orchard', and so on.

I'll give you a hint: a recursive routine is the way to go here.

Software Zen: delete this;

Fold With Us![^]

resource,h control definition problem

Caudata31-Aug-07 17:40

Caudata

31-Aug-07 17:40

I am a fairly new Visual c++ user and probably have a newbie question to ask.

I am using Visual Studio c++ v6.0 cs2 I think.

I have an array of combo box values to read in from an extremely rudimentary dialog box all created with the use of the graphical tools as much as possible.

The normal way to read data in from MFC controls seems to be to asign a variable to exchange data with the control with DDX commands and UpdateDate();.

Did I mention that I the array is fairly large? Discovering that the DDX statement doesn't even use the control's IDtag, but only the #define integer, I decided that using a large number of variables and thus a large number of DDX statements was a lot of unnecessary code and a lot of time defining variables, so I decided to get a little clever. Probably too clever...

I noticed that the resource.h file associates each control item keyword with an integer value with a #define. So I edited that file and the control box integers to reflect a series of integers that I could read control data into an array of variables with a nested for loop and one single DDX statement for a 9x9 array of combo boxes.

for (i=0; i<9; i++) {<br />
    for (j=0; j<9; j++)<br />
        {<br />
        DDX_Text(pDX, (1000+(10*j)+i), CSarray[i][j]);<br />
        }<br />
    }<br />

This actually works great . . . until, for some unexplained reason, I try to access items [6][7], [6][8], [7][6], [7][7], [7][8], [8][6], [8][7], and [8][8].
Strangely enough [6][6] works fine. These values represent the far corner combo boxes of the array.

The above code always compiles fine, but I get a run-time error - "Debug Assertion Failed!" on some file dlgdata.cpp line 43 (I have never seen this file) and I have tracked the problem by accessing each of the 81 possibilities manually. All other values read in with this method fine.

I DID have to change some other values in this file to move them out of the range of integer values I chose to make this work. (A few button controls which work fine and maybe the _APS_NEXT_CONTROL_VALUE whatever that is.) Still compiles fine. I noticed that resource.h is a header file for the ProjectName.rc file (which I don't understand at all).

So I don't have any idea what to try next. I suspect I am stepping over some value assignment limit or have a value conflict, but don't know why 1080 would work as a value when 1078 doesn't.

Re: resource,h control definition problem

chandu00431-Aug-07 18:15

chandu004

31-Aug-07 18:15

your problem seems to be solvable, but your narration is a bit confusing. so if you dont mind, you can forward me your source code, such that, i can clean it and tell you the solution.
or you can also forward me a better narration with the screen shots.

Re: resource.h control definition problem

Caudata1-Sep-07 14:32

Caudata

1-Sep-07 14:32

Here is my Resource.h:

<small>//{{NO_DEPENDENCIES}}<br />
// Microsoft Developer Studio generated include file.<br />
// Used by WinSS.rc<br />
//<br />
#define IDM_ABOUTBOX                    0x0010<br />
#define IDD_ABOUTBOX                    100<br />
#define IDS_ABOUTBOX                    101<br />
#define IDD_WINSS_DIALOG                102<br />
#define IDR_MAINFRAME                   128<br />
#define IDI_POOKA_LOGO                  130<br />
<br />
#define IDC_A1                          1000<br />
#define IDC_A2                          1001<br />
#define IDC_A3                          1002<br />
#define IDC_A4                          1003<br />
#define IDC_A5                          1004<br />
#define IDC_A6                          1005<br />
#define IDC_A7                          1006<br />
#define IDC_A8                          1007<br />
#define IDC_A9                          1008<br />
<br />
#define IDC_B1                          1010<br />
#define IDC_B2                          1011<br />
#define IDC_B3                          1012<br />
#define IDC_B4                          1013<br />
#define IDC_B5                          1014<br />
#define IDC_B6                          1015<br />
#define IDC_B7                          1016<br />
#define IDC_B8                          1017<br />
#define IDC_B9                          1018<br />
<br />
#define IDC_C1                          1020<br />
#define IDC_C2                          1021<br />
#define IDC_C3                          1022<br />
#define IDC_C4                          1023<br />
#define IDC_C5                          1024<br />
#define IDC_C6                          1025<br />
#define IDC_C7                          1026<br />
#define IDC_C8                          1027<br />
#define IDC_C9                          1028<br />
<br />
#define IDC_D1                          1030<br />
#define IDC_D2                          1031<br />
#define IDC_D3                          1032<br />
#define IDC_D4                          1033<br />
#define IDC_D5                          1034<br />
#define IDC_D6                          1035<br />
#define IDC_D7                          1036<br />
#define IDC_D8                          1037<br />
#define IDC_D9                          1038<br />
<br />
#define IDC_E1                          1040<br />
#define IDC_E2                          1041<br />
#define IDC_E3                          1042<br />
#define IDC_E4                          1043<br />
#define IDC_E5                          1044<br />
#define IDC_E6                          1045<br />
#define IDC_E7                          1046<br />
#define IDC_E8                          1047<br />
#define IDC_E9                          1048<br />
<br />
#define IDC_F1                          1050<br />
#define IDC_F2                          1051<br />
#define IDC_F3                          1052<br />
#define IDC_F4                          1053<br />
#define IDC_F5                          1054<br />
#define IDC_F6                          1055<br />
#define IDC_F7                          1056<br />
#define IDC_F8                          1057<br />
#define IDC_F9                          1058<br />
<br />
#define IDC_G1                          1060<br />
#define IDC_G2                          1061<br />
#define IDC_G3                          1062<br />
#define IDC_G4                          1063<br />
#define IDC_G5                          1064<br />
#define IDC_G6                          1065<br />
#define IDC_G7                          1066<br />
#define IDC_G8                          1067<br />
#define IDC_G9                          1068<br />
<br />
#define IDC_H1                          1070<br />
#define IDC_H2                          1071<br />
#define IDC_H3                          1072<br />
#define IDC_H4                          1073<br />
#define IDC_H5                          1074<br />
#define IDC_H6                          1075<br />
#define IDC_H7                          1076<br />
#define IDC_H8                          1077<br />
#define IDC_H9                          1078<br />
<br />
#define IDC_I1                          1080<br />
#define IDC_I2                          1081<br />
#define IDC_I3                          1082<br />
#define IDC_I4                          1083<br />
#define IDC_I5                          1084<br />
#define IDC_I6                          1085<br />
#define IDC_I7                          1086<br />
#define IDC_I8                          1087<br />
#define IDC_I9                          1088<br />
<br />
#define IDC_ABOUT_BUTTON                2000<br />
#define IDC_CONSOLE_BUTTON              2001<br />
#define IDCLEAR                         2002<br />
#define ID_CLEAR_BUTTON                 2002<br />
#define IDSOLVE                         2003<br />
#define ID_SOLVE_BUTTON                 2003<br />
#define IDC_POOKA_BYLINE                2004<br />
#define IDC_POOKA_LOGO                  2005<br />
<br />
// Next default values for new objects<br />
// <br />
#ifdef APSTUDIO_INVOKED<br />
#ifndef APSTUDIO_READONLY_SYMBOLS<br />
#define _APS_NEXT_RESOURCE_VALUE        134<br />
#define _APS_NEXT_COMMAND_VALUE         32771<br />
#define _APS_NEXT_CONTROL_VALUE         2000<br />
#define _APS_NEXT_SYMED_VALUE           101<br />
#endif<br />
#endif</small>

Here is the code from the ProjectNameDlg.cpp file meant to retreive the data from the 9x9 array of combo box controls:

<small>    CString CSarray[9][9];<br />
<br />
	int i,j; // (i = 0..9), (j = A .. I)<br />
// These values of (a,b) fail with the error Debug Assertion Failed<br />
// meaning that their values were incorrect or out of bounds<br />
<br />
//	int a= 6;<br />
//	int b= 7;<br />
<br />
//	int a= 6;<br />
//	int b= 8;<br />
<br />
//	int a= 7;<br />
//	int b= 6;<br />
<br />
//	int a= 7;<br />
//	int b= 7;<br />
<br />
//	int a= 7;<br />
//	int b= 8;<br />
<br />
//	int a= 8;<br />
//	int b= 6;<br />
<br />
//	int a= 8;<br />
//	int b= 7;<br />
<br />
//	int a= 8;<br />
//	int b= 8;<br />
<br />
	int a= 6;<br />
	int b= 6;<br />
<br />
	for (i=0; i<9; i++) {<br />
		for (j=0; j<9; j++)<br />
			{<br />
//			DDX_Text(pDX, (1000+(10*b)+a), CSarray[i][j]);<br />
			DDX_Text(pDX, (1000+(10*j)+i), CSarray[i][j]);<br />
			}<br />
		}<br />
         }<br />
<br />
</small>

I am getting a "Debug Assertion Failure! (File:dlgdata.cpp line 43 - which doesn't exist)" for the 8 combo boxes commented above. I cannot find a logical reason why these controls cause this failure when none of the others do. Is there some limitation of Visual c++ v6.0 on the number of control boxes allowed?

Re: resource,h control definition problem

Caudata1-Sep-07 18:32

Caudata

1-Sep-07 18:32

The Problem eventually solved itself. Turns out, when modifying one of the control's label and re-saving the dialog editor window, the problem just went away. Must be some feature of Visual c++ that has a copy of the information somewhere else that needs to be updated.

Very strange (and annoying) behavior. But case closed.

Trouble with const

Leslie Sanford31-Aug-07 13:19

Leslie Sanford

31-Aug-07 13:19

This one has left me scracthing my head. I want to define a constant array in an implementation file. I'd like to treat it as a read only table. So in my implementation file I have this:

const unsigned char Sawtooth[] =
{
    // A bunch of values.
};

In my header file, I have this:

extern const unsigned char Sawtooth[];

When I try to build the solution, I get an unresolved external symbol error. If I remove const from both the declaration and the definition, it compiles fine. It's as though the const modifier is making the definition private to the implementation file, like the static modifier does.

I don't remember having this problem using C. Is this a C++ or Visual Studio "gotcha" that I've not been aware of before? Or is there something else I'm overlooking?

Re: Trouble with const

Mark Salsbery31-Aug-07 13:26

Mark Salsbery

31-Aug-07 13:26

It works for me on VS 2005.

Mark

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

Re: Trouble with const

Leslie Sanford31-Aug-07 13:41

Leslie Sanford

31-Aug-07 13:41

Mark Salsbery wrote:
It works for me on VS 2005.

It seems to have a problem when I assign the const array to a member variable in one of my classes. So in one of my classes, I have this:

private:
    const unsigned char *wavetable;

And I have a setter method in the same class:

void Oscillator::SetWavetable(const unsigned char *wavetable)
{
    assert(wavetable != 0);
 
    this->wavetable = wavetable;
}

If I remove the assignment, the compiler error goes away. I don't understand what the problem is. I'm declaring/defining a const unsigned char array in an implementation file. I pass it to the above method and for some reason the compiler is treating it as a "unsigned char const * const", according to the compiler error message.

Re: Trouble with const

Mark Salsbery31-Aug-07 13:52

Mark Salsbery

31-Aug-07 13:52

Leslie Sanford wrote:
seems to have a problem when I assign the const array to a member variable

I don't see any code assigning an array to a member variable.

Your code shown built fine for me as well Smile | :)

Mark

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

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