C / C++ / MFC Discussion Boards

Re: Urgent: Having problem with while loop

dreamerzz5-Apr-04 21:56

5-Apr-04 21:56

Hi hi,

Thanks for the codings that is provided. Much appreciated. However, i am unfamiliar with using THREADS. But will give it a try on the codings that you provided. In the meantime, is there any other solution to this problem??

Thanks lots Smile | :)

Re: Urgent: Having problem with while loop

avenger_sb256-Apr-04 5:30

avenger_sb25

6-Apr-04 5:30

Hey, i've got another solution for u (that too WITHOUT threads Wink | ;)

)

//----------make a global var----------
//glo can take two values>>
//0:do nohting; 1:update the values; int glo=0;
DO idle-time processing- i think the function is OnIdle() for CwinApp (i'm not sure about MFC, find it urself)
The OnIdle function is executed when ur window doesnt receive any key input.
OnIdle is executed all time but it will update ur values only when glo is 1.
The following code will ensure this:

CWinApp::OnIdle()<br />
{<br />
 if(glo==0)<br />
 ; //do nothing<br />
 else if(glo==1)<br />
 {<br />
 //write all ur updating stuff here<br />
 }<br />
}

Inside Update Button click function, all u have to do is to set the value of glo to 1.
//---------Update button click rotine-----

OnUpdateClick()<br />
{<br />
 glo=1;<br />
}

Inside Stop Button click function, all u have to do is to reset the value of glo to 0. This will stop the update.(;))
//---------Update button click rotine-----

OnStopClick()<br />
{<br />
 glo=0;<br />
<br />
//NOW WRITE UPDATED VALUES TO DATABASE<br />
}

Thats allllllll...........

...Avenger

^{Remember... testing & debugging are always part of programming ...so exterminate those stinking bugs}

Re: Urgent: Having problem with while loop

dreamerzz9-Apr-04 6:04

dreamerzz

9-Apr-04 6:04

Hi,
For this thread function, i have some doubts which i have stated below. Can kindly explain to me? Thanks

For this function that you have stated:
DWORD WINAPI UpdateThread(LPVOID lpParameter)

I just need to copy down or do i have to state any values to the lpParameter?

Here, i have also attached part of the codings that i have done, but i have tried the methods that you have given but it dun seems to work the way as you state. The coding stated below, the while loop is working and the database will be updated on click the UpdateDB. however, once i click on the update button, the whole program seems to hang.

<br />
//global variables<br />
int check_exit=0;<br />
<br />
//Update button function<br />
void CUpdateView::OnUpdatedb() <br />
{<br />
	// TODO: Add your control notification handler code here<br />
<br />
	//get a pointer to the recordset<br />
		CUpdateDoc* pDoc = GetDocument();<br />
		UseRecordset* pUseRecordset	= &pDoc->m_UseRecordset;<br />
	int x = 5;<br />
	do<br />
	{<br />
		pUseRecordset->Edit();<br />
<br />
		//UpdateData(true);	<br />
		pUseRecordset->m_propatime = m_propagation*x;<br />
	<br />
		pUseRecordset->Update();<br />
<br />
		if (check_exit = 0)<br />
			check_exit=1;	<br />
	}while(check_exit!=1);<br />
<br />
	//::MessageBox(0, "Updated!", "Information",0);<br />
}<br />
<br />
//Exit button function<br />
void CUpdateView::OnExit() <br />
{<br />
	check_exit = 0;<br />
}

Thanks a million,
dreamerzz

Re: Urgent: Having problem with while loop

avenger_sb259-Apr-04 7:57

avenger_sb25

9-Apr-04 7:57

if (check_exit = 0)
If this is what you have coded, then change it to:
if (check_exit == 0)

LOOK CLOSE AT UR PROGRAM, it doesnt come out of the do-while loop

Well, if you have written that by mistake and are actually using if (check_exit == 0) then your program is hanging because it keeps looping inside the do-while LOOP. ACTUALLY UR PROGRAM APPEARS TO HANG(loops & loops and loops) AS IT DOESNT RETURN CONTROL BACK TO WINDOWS(ur main program), so you can no longer interact with any other buttons.

The trick is to run a continious LOOPING do-while LOOP, but we want it to run seperately from our main program. HERE COMES THE THREAD:::>>>

int loop=1; //1 means keep looping 0 means stop and end the thread
DWORD WINAPI UpdateThread(LPVOID lpParameter)
{
//get a pointer to the recordset
CUpdateDoc* pDoc = GetDocument();
UseRecordset* pUseRecordset = &pDoc->m_UseRecordset;
int x = 5;

while(loop==1)
{
pUseRecordset->Edit();

//UpdateData(true); 
pUseRecordset->m_propatime = m_propagation*x;

pUseRecordset->Update();
}
}

THE ABOVE FUNCTION DOES NOTHING. IT DOESNOT START A NEW THREAD. It is like any ordinary function function defination. Its has to be called from somewhere to make it execute. BUT UNLIKE ORDINARY FUNTIONS, we will not call UpdateThread(<<something>>) as it will not start a new thread.

And the name "UpdateThread" is purely arbitrary. You can name the thread as "dreamerzz Thread()" or "CrapThread()" or "BoomBoom()" or whatever you want.

Now, we want this thread to start when we click Update buttom. so, we write::>>>

//------global data------
HANDLE hthread; // this is thread handle
int idThread; // this is threaed id

//Update button function
void CUpdateView::OnUpdatedb() 
{
// TODO: Add your control notification handler code here

// in place of "UpdateThread" use whatever you have named the thread
hThread=CreateThread(NULL,0,UpdateThread,0,0,&idThread); 
}

You dont have to explicitly end the thread as it will automatically terminate when the value of "loop" becomes 0. (To explicitly terminate a thread you can use the function TerminateThread(hThread,0);)

//Exit button function
void CUpdateView::OnExit() 
{
loop = 0;
}

Ask if u have doubts

...Avenger

Remember... testing & debugging are always part of programming ...so exterminate those stinking bugs

Re: Urgent: Having problem with while loop

dreamerzz20-Apr-04 2:20

dreamerzz

20-Apr-04 2:20

Hi,

Thanks for the help given.;)

dReaMerzZ

please help me have a look at below "onInitDialog()",why return true at the end?

vividtang3-Apr-04 2:16

vividtang

3-Apr-04 2:16

BOOL CTest02Dlg::OnInitDialog()
{
CDialog::OnInitDialog();

// IDM_ABOUTBOX must be in the system command range.
ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
ASSERT(IDM_ABOUTBOX < 0xF000);

CMenu* pSysMenu = GetSystemMenu(FALSE);
if (pSysMenu != NULL)
{
CString strAboutMenu;
strAboutMenu.LoadString(IDS_ABOUTBOX);
if (!strAboutMenu.IsEmpty())
{
pSysMenu->AppendMenu(MF_SEPARATOR);
pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
}
}

// Set the icon for this dialog. The framework does this automatically
// when the application's main window is not a dialog
SetIcon(m_hIcon, TRUE); // Set big icon
SetIcon(m_hIcon, FALSE); // Set small icon

// TODO: Add extra initialization here

return TRUE; // return TRUE unless you set the focus to a control
}

Re: please help me have a look at below "onInitDialog()",why return true at the end?

Gary R. Wheeler3-Apr-04 2:49

Gary R. Wheeler

3-Apr-04 2:49

Normally, when a dialog opens, Windows will set the focus to the first control in the dialog in the tab order. You can override this behavior in OnInitDialog() by setting the focus yourself to some other control. If you return FALSE from OnInitDialog(), Windows assumes that you've set the focus to the control you want, and it will not set the focus as it usually does. Return TRUE to get the normal behavior.

Software Zen: delete this;

GetNetworkParams & GetAdaptersInfo

Anonymous3-Apr-04 2:06

Anonymous

3-Apr-04 2:06

Hi,
Can anyone equivalent APIs of GetNetworkParams & GetAdaptersInfo to work on Windows NT 4.0.

Thanks, Blush | :O

Scolling of BIG document

Still learning how to code3-Apr-04 1:08

Still learning how to code

3-Apr-04 1:08

Hi, I'm working on an app using a view class based on CScrollView. As the doc is BIG, I've hit the 32768 'limit' of SetScrollSizes(). I'm sure I remember seeing an article on CP about getting around this problem, but can I find it ?? Can someone point me in the right direction please !! ?

Doug

Re: Scolling of BIG document

Gary R. Wheeler3-Apr-04 2:12

Gary R. Wheeler

3-Apr-04 2:12

Use SetScrollInfo instead.

Software Zen: delete this;

Re: Scolling of BIG document

Still learning how to code3-Apr-04 7:47

Still learning how to code

3-Apr-04 7:47

Hi Gary, Yes, I've just stumbled over that and am now over the problem. Thanks, Doug

Doug

map container

MatthewP3-Apr-04 0:57

MatthewP

3-Apr-04 0:57

Can someone please explain 1) the effect of "op" in each of these three map initializations below, 2)why op needs to be a class or struct as an overloaded () operator , and 3) why when I use #3 I loose the ability to access an element using map[key], such as ++map[key]. Thanks!

1) map<key, elem,="" op=""> m;
2) map<key, elem=""> m(op);
3) map<key, elem,="" op=""> m(op);

Where I've seen these for reference:
1) The C++ Standard Library, page 196.
2) Accelerated C++, page 137.
3) Accelerated C++, page 321.

Matthew

Re: map container

MatthewP3-Apr-04 4:06

MatthewP

3-Apr-04 4:06

Sorry, the examples didn't print out right:

1) map<key, elem, op> m;
2) map<key, elem> m(op);
3) map<key, elem, op> m(op);

Matthew

how to make button control colorful .

vividtang2-Apr-04 23:08

vividtang

2-Apr-04 23:08

how to make button control colorful .

Re: how to make button control colorful .

gUrM33T3-Apr-04 0:31

gUrM33T

3-Apr-04 0:31

MSDN Documentation states:

Buttons with the BS_PUSHBUTTON, BS_DEFPUSHBUTTON, or BS_PUSHLIKE styles do not use the returned brush. Buttons with these styles are always drawn with the default system colors. Drawing push buttons requires several different brushes-face, highlight and shadow-but the WM_CTLCOLORBTN message allows only one brush to be returned. To provide a custom appearance for push buttons, use an owner-drawn button.

Gurmeet S. Kochar

If you believe in God, it's because of the Devil

Re: how to make button control colorful .

Monty²3-Apr-04 0:38

Monty²

3-Apr-04 0:38

is this[^] color full enough Smile | :)

C makes it easy to shoot yourself in the foot; C++ makes it harder, but when you do, it blows away your whole leg

HWND TO string and string to HWND conversion

Atif Mushtaq2-Apr-04 21:46

Atif Mushtaq

2-Apr-04 21:46

so far i am able to convert HWND to string but i am not able to find a way to convert string to HWND .

There is a way to convert hex string to int but not hex.

so either someone tell me int to hex conversion or direct string to hex.

Unmanaged in a .NET world

Re: HWND TO string and string to HWND conversion

Maxwell Chen2-Apr-04 22:09

Maxwell Chen

2-Apr-04 22:09

string sApple = "463A";
long lNum;
char* pE;
lNum = strtol(sApple.c_str(), &pE, 16);
printf("0x%X\n", lNum);
HWND hW = (HWND)lNum;

<b>Maxwell Chen</b>

Re: HWND TO string and string to HWND conversion

Atif Mushtaq2-Apr-04 22:57

Atif Mushtaq

2-Apr-04 22:57

Thanx very much , it really worked , thanx

Unmanaged in a .NET world

Display a MessageBox right after a dialog is drawn on the screen?

usfesco2-Apr-04 21:29

usfesco

2-Apr-04 21:29

hi all,

I would like my dialog-based app to pop up a message box right after the dialog itself is shown on the screen... anyone knows how to do that?

If I put a message box in my dialog's OnInitDialog like this:

BOOL CTestDlg::OnInitDialog()<br />
{<br />
	CDialog::OnInitDialog();<br />
......<br />
  AfxMessageBox("hello");	<br />
	return TRUE;  // return TRUE  unless you set the focus to a control<br />
}

the message box pops up before the main dialog appears, but I want the message box to pop up AFTER the main dialog appears. I've tried handling WM_SHOWWINDOW message, i.e., put the AfxMessageBox in the dialog's OnShowWindow() function, but it was the same thing as putting the AfxMessageBox in OnInitDialog() -- the message box still pops up before the main dialog appears.

Thanks for your help in advance Blush | :O

Re: Display a MessageBox right after a dialog is drawn on the screen?

PJ Arends3-Apr-04 8:30

PJ Arends

3-Apr-04 8:30

The easist way is post a custom message to your dialog from the OnInitDialog function, that way OnInitDialog will close, and the dialog will be created before the message is handled. In the custom message handler you call AfxMessageBox.

#define WMU_POPUPMESSAGEBOX WM_APP;
...
BEGIN_MESSAGE_MAP(CTestDlg, CDialog)
...
    ON_MESSAGE(WMU_POPUPMESSAGEBOX, OnPopupMessageBox)
END_MESSAGE_MAP()
...
BOOL CTestDlg::OnInitDialog()
{
...
    PostMessage(WMU_POPUPMESSAGEBOX, 0, 0);
    return TRUE;
}
 
HRESULT OnPopupMessageBox(WPARAM, LPARAM)
{
    AfxMessageBox(_T("Hello"));
    return 0;
}

Sonork 100.11743 Chicken Little

"You're obviously a superstar." - Christian Graus about me - 12 Feb '03

Within you lies the power for good - Use it!

Re: Display a MessageBox right after a dialog is drawn on the screen?

usfesco3-Apr-04 14:10

usfesco

3-Apr-04 14:10

Thanks dear Mr. Arends, It Worked! Rose | [Rose]

Re: Display a MessageBox right after a dialog is drawn on the screen?

avenger_sb255-Apr-04 7:55

avenger_sb25

5-Apr-04 7:55

Hey, i used the following technique in my program to solve a same problem.

when you recieve WM_INITDIALOG message, call ShowWindow(hDlg,SW_SHOW); //plese write the MFC equivalent urself;P)

After that, you can call MessageBox to do your stuff...

That's simpler solution.

^{Remember... testing & debugging are always part of programming ...so exterminate those stinking bugs}

Scrollbars

Member 9541232-Apr-04 21:24

Member 954123

2-Apr-04 21:24

Hi ,
When i use the scrollbars the position of the window also changes.
Can i attach my code instead of pasting it?
Thanks and regards,
Salil.

CString szFilename("d:\\vc\\mfc\\2001.bmp");
HBITMAP hBmp = (HBITMAP)::LoadImage(NULL,szFilename,
IMAGE_BITMAP,0,0,
LR_LOADFROMFILE|LR_CREATEDIBSECTION);
CBitmap bmp;
bmp.Attach(hBmp);
CClientDC dc(this);
CDC bmDC;
bmDC.CreateCompatibleDC(&dc);
CBitmap *pOldbmp = bmDC.SelectObject(&bmp);
BITMAP bi;
bmp.GetBitmap(&bi);
dc.StretchBlt (0,0,len_in_pix,ht_in_pix,&bmDC,0,0,bi.bmWidth
,bi.bmHeight,SRCCOPY);
bmDC.SelectObject(pOldbmp);

CString szFilename1("d:\\vc\\mfc\\2002.bmp");
HBITMAP hBmp1 = (HBITMAP)::LoadImage(NULL,szFilename1,
IMAGE_BITMAP,0,0,
LR_LOADFROMFILE|LR_CREATEDIBSECTION);
CBitmap bmp1;
bmp1.Attach(hBmp1);
CClientDC dc1(this);
CDC bmDC1;
bmDC1.CreateCompatibleDC(&dc1);
CBitmap *pOldbmp1 = bmDC1.SelectObject(&bmp1);
BITMAP bi1;
bmp1.GetBitmap(&bi1);
dc1.StretchBlt (0,br_in_pix,len_in_pix,ht_in_pix,&bmDC1,0,0,bi.bmWidth
,bi.bmHeight,SRCCOPY);
bmDC1.SelectObject(pOldbmp1);

CString szFilename2("d:\\vc\\mfc\\2003.bmp");
HBITMAP hBmp2 = (HBITMAP)::LoadImage(NULL,szFilename2,
IMAGE_BITMAP,0,0,
LR_LOADFROMFILE|LR_CREATEDIBSECTION);
CBitmap bmp2;
bmp2.Attach(hBmp2);
CClientDC dc2(this);
CDC bmDC2;
bmDC2.CreateCompatibleDC(&dc2);
CBitmap *pOldbmp2 = bmDC2.SelectObject(&bmp2);
BITMAP bi2;
bmp2.GetBitmap(&bi2);
dc2.StretchBlt (0,br_in_pix+ht_in_pix,len_in_pix,br_in_pix,&bmDC2,0,0,bi.bmWidth
,bi.bmHeight,SRCCOPY);
bmDC2.SelectObject(pOldbmp2);

CString szFilename3("d:\\vc\\mfc\\2004.bmp");
HBITMAP hBmp3 = (HBITMAP)::LoadImage(NULL,szFilename3,
IMAGE_BITMAP,0,0,
LR_LOADFROMFILE|LR_CREATEDIBSECTION);
CBitmap bmp3;
bmp3.Attach(hBmp3);
CClientDC dc3(this);
CDC bmDC3;
bmDC3.CreateCompatibleDC(&dc3);
CBitmap *pOldbmp3 = bmDC3.SelectObject(&bmp3);
BITMAP bi3;
bmp3.GetBitmap(&bi3);
dc3.StretchBlt (0,2*br_in_pix+ht_in_pix,len_in_pix,ht_in_pix,&bmDC3
,0,0,bi.bmWidth,bi.bmHeight,SRCCOPY);

bmDC3.SelectObject(pOldbmp3);

CString szFilename4("d:\\vc\\mfc\\2005.bmp");
HBITMAP hBmp4 = (HBITMAP)::LoadImage(NULL,szFilename4,
IMAGE_BITMAP,0,0,
LR_LOADFROMFILE|LR_CREATEDIBSECTION);
CBitmap bmp4;
bmp4.Attach(hBmp4);
CClientDC dc4(this);
CDC bmDC4;
bmDC4.CreateCompatibleDC(&dc4);
CBitmap *pOldbmp4 = bmDC4.SelectObject(&bmp4);
BITMAP bi4;
bmp4.GetBitmap(&bi4);
dc4.StretchBlt (0,2*br_in_pix+2*ht_in_pix,len_in_pix,20,&bmDC4
,0,0,bi.bmWidth,20,SRCCOPY);

bmDC4.SelectObject(pOldbmp4);

void CAprsView::OnSize(UINT nType, int cx, int cy)
{
CScrollView::OnSize(nType, cx, cy);

// TODO: Add your message handler code here
if(GetSafeHwnd() != NULL) {
SetScrollers();
}
}

void CAprsView::SetScrollers()
{

CRect image;
GetWindowRect(&image);
ScreenToClient(&image);

CRect view;
GetClientRect(&view);

//****************************************************************
// Vertical Scrollbar setting
//****************************************************************
SCROLLINFO info;
::ZeroMemory(&info, sizeof(info));
info.cbSize = sizeof(info);

// Do not disable the scrollbar if the image is scrolled
// off the top; it must be vertically entirely
// scrolled on to disable the scrollbars

if(image.top == 0 && image.Height() < view.Height())
{ // no vert scrolling

info.nMin = 0;
info.nMax = 0;
info.fMask = SIF_RANGE;
} //no vert scrolling

else
{ // vert scrolling
info.nMin = 0;
info.nMax = image.Height();
// The code below fiddles the page size to keep
// the scrollbar from disappearing when the page size
// equals the scroll range, a feature of the built-in
// control
if(image.top < 0 && view.Height() >= image.Height())
{ // need more
info.nPage = image.Height() + image.top + 1;
} // need more
else
{ // just fine
info.nPage = view.Height();
} // just fine

info.fMask = SIF_RANGE | SIF_PAGE;
} // vert scrolling
SetScrollInfo(SB_VERT, &info);

//****************************************************************
// Horizontal Scrollbar setting
//****************************************************************

::ZeroMemory(&info, sizeof(info));
info.cbSize = sizeof(info);
if(image.left == 0 && image.Width() < view.Width())
{ //no horz scrolling
info.nMin = 0;
info.nMax = 0;
info.fMask = SIF_RANGE;
} // no horz scrolling
else
{ // horz scrolling
info.nMin = 0;
info.nMax = image.Width(); // - view.Width();
if(image.top < 0 && view.Width() >= image.Width())
{ // need more
info.nPage = image.Width() + image.top + 1;
} // need more
else
{ // just fine
info.nPage = view.Width();
} // just fine
info.fMask = SIF_RANGE | SIF_PAGE;
} // horz scrolling
SetScrollInfo(SB_HORZ, &info);

}

void CAprsView::OnInitialUpdate()
{
CScrollView::OnInitialUpdate();

// TODO: Add your specialized code here and/or call the base class

CSize sizeTotal;
// TODO: calculate the total size of this view
sizeTotal.cx = sizeTotal.cy = 100;
SetScrollSizes(MM_TEXT, sizeTotal);
}

void CAprsView::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
// TODO: Add your message handler code here and/or call default
int newpos = GetScrollPos(SB_HORZ);
SCROLLINFO info;
::ZeroMemory(&info, sizeof(info));
info.cbSize = sizeof(info);
info.fMask = SIF_RANGE | SIF_PAGE | SIF_POS | SIF_TRACKPOS;
GetScrollInfo(SB_HORZ, &info);

int low = info.nMin;
int high = info.nMax - info.nPage;

CRect view;
GetClientRect(&view);

CRect image;
GetWindowRect(&image);
ScreenToClient(&image);

switch(nSBCode)
{ /* nSBCode */
case SB_LINEUP:
newpos -= ::GetSystemMetrics(SM_CXVSCROLL);
if(newpos < low)
newpos = low;
break;
case SB_LINEDOWN:
newpos += ::GetSystemMetrics(SM_CXVSCROLL);
if(newpos > high)
newpos = high;
break;
case SB_PAGEUP:
newpos -= view.Height();
if(newpos < low)
newpos = low;
break;
case SB_PAGEDOWN:
newpos += view.Height();
if(newpos > high)
newpos = high;
break;
case SB_THUMBTRACK:
newpos = info.nTrackPos;
break;
case SB_THUMBPOSITION:
newpos = info.nTrackPos;
break;
} /* nSBCode */
SetScrollPos(SB_HORZ, newpos);
SetWindowPos(NULL, -newpos , image.top, 0, 0, SWP_NOSIZE | SWP_NOZORDER);

CScrollView::OnHScroll(nSBCode, nPos, pScrollBar);
}

void CAprsView::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
// TODO: Add your message handler code here and/or call default
SCROLLINFO info;
::ZeroMemory(&info, sizeof(info));
info.cbSize = sizeof(info);
info.fMask = SIF_RANGE | SIF_PAGE | SIF_POS | SIF_TRACKPOS;
GetScrollInfo(SB_VERT, &info);

int low = info.nMin;
int high = info.nMax - info.nPage;
int newpos = info.nPos;

CRect view;
GetClientRect(&view);

CRect image;
GetWindowRect(&image);
ScreenToClient(&image);

switch(nSBCode)
{ /* nSBCode */
case SB_LINEUP:
newpos -= ::GetSystemMetrics(SM_CYHSCROLL);
if(newpos < low)
newpos = low;
break;
case SB_LINEDOWN:
newpos += ::GetSystemMetrics(SM_CYHSCROLL);
if(newpos > high)
newpos = high;
break;
case SB_PAGEUP:
newpos -= view.Height();
if(newpos < low)
newpos = low;
break;
case SB_PAGEDOWN:
newpos += view.Height();
if(newpos > high)
newpos = high;
break;
case SB_THUMBTRACK:
newpos = info.nTrackPos;
break;
case SB_THUMBPOSITION:
newpos = info.nTrackPos;
break;
} /* nSBCode */
SetScrollPos(SB_VERT, newpos);
SetWindowPos(NULL,image.left,-newpos,0, 0, SWP_NOSIZE | SWP_NOZORDER);

CScrollView::OnVScroll(nSBCode, nPos, pScrollBar);
}

How to Make a Form based Application Window fixed

swarnamanoo2-Apr-04 21:00

swarnamanoo

2-Apr-04 21:00

I have a form based application window and i need to make its size fixed.How do i do it.

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.