C / C++ / MFC Discussion Boards

LakshmiPathiRao19-Jul-06 2:22

19-Jul-06 2:22

Hai to all,

i am connecting to Access DataBase
In one case i want to delete all rows in my table
so that i have written a code like this

cData1 is a class derived from CRecordSet.
CData1 rs;
rs.Open();
rs.MoveFirst();
while(!rs.IsEOF())
{
rs.Delete();
rs.MoveNext();
rs.Update();
}
rs.Close();
It is giving error like this
Attempt to update or delete failed

can any one help me plsssssssss
thanks in advance

B.LakshmiPathiRao.
VC++ Programer

-- modified at 2:19 Thursday 20th July, 2006

Re: Problem on DataBase Update

David Crow19-Jul-06 2:41

David Crow

19-Jul-06 2:41

LakshmiPathiRao wrote:
rs.MoveNext();
rs.Update();

I believe these are in the wrong order.

Why not something simple like:

CDatabase db;
db.ExecuteSQL("DELETE FROM table);

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

Re: Problem on DataBase Update

Tara1419-Jul-06 22:37

Tara14

19-Jul-06 22:37

I guess it is to do with Update.
See MSDN help. It say's

Unlike AddNew and Edit, a call to Delete is not followed by a call to Update.

Fortitudine Vincimus!

how can I call a .exe in c++

mwolf12219-Jul-06 2:16

mwolf122

19-Jul-06 2:16

How can I call a .exe file in a c/c++(not MFC) project?

thx,
L Zhang

Re: how can I call a .exe in c++

Anilkumar K V19-Jul-06 2:18

Anilkumar K V

19-Jul-06 2:18

ShellExecute
system
WinExec
CreateProcess

Re: how can I call a .exe in c++

Cedric Moonen19-Jul-06 2:19

Cedric Moonen

19-Jul-06 2:19

mwolf122 wrote:
How can I call a .exe file

You mean launching an exe, no ? If yes, see the FAQ[^]

Cédric Moonen
Software developer

Charting control

Re: how can I call a .exe in c++

Hamid_RT19-Jul-06 2:31

Hamid_RT

19-Jul-06 2:31

See ShellExecute[^]

whitesky

Re: how can I call a .exe in c++

mwolf12219-Jul-06 21:36

mwolf122

19-Jul-06 21:36

thx,
it already works.

SetTimer, nIDEvent and timer identification

Dimitris Vikeloudas19-Jul-06 1:41

Dimitris Vikeloudas

19-Jul-06 1:41

I want to use timers do some actions.

I read about
UINT SetTimer(HWND hWnd, UINT nIDEvent, UINT uElapse, TIMERPROC lpTimerFunc );

versus the

CWnd::SetTimer, UINT nIDEvent, UINT uElapse, TIMERPROC lpTimerFunc );

There is a nice document here explaining some facts. However, I still have some questions about who is handling the timers.

I want to create and handle the timers inside a CScrollView (by mapping and overwriting the inherited CWnd::OnTimer(UINT nIDEvent) and not via a TIMERPROC.

However, I am not sure which timer creation function to use and what value will be good for the nIDEvent on them.

i. How do I guarantee that the CScrollView which created the timer is the one that receives the WM_TIMER message (and subsequently process it). Is it possible that the
WM_TIMER expiration message ends up on another queue (I found that this is possible for mouse messages) or only the creating window can get it?

ii. Is the nIDEvent identifier a system unique one or a view unique one? How do I get a sufficiently unique nIDEvent value to make sure that I am processing the right timer?

iii. Is it possible that my CScrollView will receive time outs (i.e. WM_TIMER messages) by other views or even other threads or applications and under which conditions? If yes what should I do with those timers?

iv. Any idea why SetTimer may fail? Is this due to a system limit on running timers or due to a non unique nIDEvent? How can I know?

Dimitris

Re: SetTimer, nIDEvent and timer identification

Kurt _B19-Jul-06 2:57

Kurt _B

19-Jul-06 2:57

i. If you do "this->SetTimer(100, 2000, NULL)" inside your CScrollView class it will use the handle for your view.

ii. It is unique to your view. How many timers are you planning on using? If just one declare a constant.

iii. Yes if some sends the WM_TIMER message to that view. Really shouldn't happen though.

iv. How do you know it's failing?

Re: SetTimer, nIDEvent and timer identification

Dimitris Vikeloudas19-Jul-06 3:17

Dimitris Vikeloudas

19-Jul-06 3:17

Thanks a lot. It clarifies a lot of things.

Thus, I can be sure that my view and only this will handle the timers. My plans are to use one timer primarely but there are some rare cases that I may have two running similtaneously. However, if their ids are view unique ones I can use constants to guarantee uniquness and I am assuming that noone sends to my view a WM_TIMER message (according to what you said it sounds a reasonable assumption. Note that the thread will have more than one CScroll views of the same or different type).

According to my reading SetTimer indicates failure if it returns zero. Thus, I know that it is failed to create a timer. But it seems to me that this is due to system resources limits thus, nothing that I can do about it.

Well, was quite helpfull clarifying these points, hope now that they will work like these.

Dimitris...

Re: SetTimer, nIDEvent and timer identification [modified]

bosfan19-Jul-06 4:06

bosfan

19-Jul-06 4:06

Hello,
do you have:

ON_WM_TIMER()
in your Messagemap included??
than you have to call the function like this:

<br />
// but befor call OnTimer you have first set the timer in some other funktion:<br />
int SomeOtherFunc()<br />
{<br />
nIDEvent = SetTimer(iTimerIdentifier, iIntervalMiliSecond,0); //iTimerIdentifier is stored in nIDEvent for use in OnTimer(UINT nIDEvent), iIntervalMiliSecond is the time to wait between intervals<br />
// example<br />
nIDEvent = SetTimer(2, 1000,0);<br />
}<br />
afx_msg void MyAppDlg::OnTimer(UINT nIDEvent)<br />
{<br />
// do something with this nIDEvent<br />
switch(nIDEvent)<br />
{<br />
case 1:<br />
{<br />
...<br />
break;<br />
}<br />
case 2:<br />
{<br />
// in my example the OnTimer jump here, and i can do something ...<br />
<br />
...<br />
break;<br />
}<br />
//etc.<br />
default:<br />
break;<br />
}<br />
}<br />
<br />
....<br />

give peace of code to see what you coding to set and start timer!

break;

-- modified at 11:13 Wednesday 19th July, 2006

Menus Disable when Switch from One View to Another View. [modified]

Uday Janaswamy19-Jul-06 1:30

Uday Janaswamy

19-Jul-06 1:30

hi all,

when i switch from one CFormView to Another CFormView, I am observing that my menu items for the second form are Disabled. I cant Understand why this is Happen when i switch from one view to another.

//---------Code -----------------------------------//

void CMainFrame::SwitchView()
{
CView *pOldView;
CView *pNewView;

pOldView = GetActiveView();

if (m_pCFirstView == NULL)
m_pCFirstView = pOldView;

if (m_pCSecondView == NULL)
{
CRuntimeClass *pCR = RUNTIME_CLASS(CSecondView);
m_pCSecondView = static_cast<cview*>(pCR->CreateObject());
m_pCSecondView->Create(NULL,NULL,AFX_WS_DEFAULT_VIEW,rectDefault,this,AFX_IDW_PANE_FIRST+1,NULL);
}
if (m_bFirstViewActive)
pNewView = m_pCSecondView;
else
pNewView = m_pCFirstView;
int nChildId = pNewView->GetDlgCtrlID();
pNewView->SetDlgCtrlID(AFX_IDW_PANE_FIRST);
pOldView->SetDlgCtrlID(nChildId);

CDocument *pDoc = pOldView->GetDocument();
pDoc->AddView(pNewView);
pDoc->RemoveView(pOldView);
SetActiveView(pNewView);
RecalcLayout();
pNewView->ShowWindow(SW_SHOW);
pOldView->ShowWindow(SW_HIDE);
m_bFirstViewActive = !m_bFirstViewActive;
}
//-----------------------------//------------------------------------//

Every thing is Ok but the Menu Items are Enabled when i transform from View to Another View. Please Provide me good Solution.

is there any Custom Command Routing for this.

please help me out.

uday.

-- modified at 7:36 Wednesday 19th July, 2006

Re: Menus Disable when Switch from One View to Another View.

Steve S19-Jul-06 1:49

Steve S

19-Jul-06 1:49

Do you have UI updating defined only in one view, then?

Normally the view will get a crack at updating menu item states. If there's no handler, and no update handler, a menu item will get disabled.

Steve S
Developer for hire

Re: Menus Disable when Switch from One View to Another View.

Uday Janaswamy19-Jul-06 1:57

Uday Janaswamy

19-Jul-06 1:57

hi steve,

Should i take Command Handlers in View or CFrameWnd, Shall i take in What order to this Problem.

Please help me out.

uday.

Re: Menus Disable when Switch from One View to Another View.

Steve S19-Jul-06 6:34

Steve S

19-Jul-06 6:34

You can handle commands (and hence UI updating) in any of:

Frame - if you've derived your own frame window
Document - even though it isn't a window!
View - the active one

There is a series of articles in MSJ (now MSDN magazine) which you should still be able to find at the MSDN website, that explain how the routing works in some depth. Essentially, it's up to you as the app designer to determine where the appropriate/correct place for handlers is. For example, handling File/Print would generally be in the document class (since it applies irrespective of the view), whereas edit menu items tend to be managed by the view. If you have multiple views (either SDI switching or MDI) then it is perfectly possible that you have handlers in each view. However, only one of these handlers/UI updates will be called, and it will be the one in the object associated with the active view.

Steve S
Developer for hire

TAB CONTROL [modified]

ashish dogra19-Jul-06 0:38

ashish dogra

19-Jul-06 0:38

plz tell me answer for this
i want to know is this code work when i click tab1 on tab control
i try this but not do the work.
void CGouravDlg::OnSelchangeTab1(NMHDR* pNMHDR, LRESULT* pResult)
{
// TODO: Add your control notification handler code here
CBrush brush;
CDC *pDC;
if(BN_CLICKED(IDC_TAB1))
{
brush.CreateSolidBrush(RGB(100,0,0));
pDC->SetBkColor(RGB(100,0,0));
// m_tab.SendMessage(WM_PAINT,0L,0L);
}
*pResult = 0;
}

Ashish Dogra
MCA
Noida

-- modified at 7:24 Wednesday 19th July, 2006

Re: TAB CONTROL

Hamid_RT19-Jul-06 2:27

Hamid_RT

19-Jul-06 2:27

I dont know why you ask this question repeated I reply to you in previous thread and you can find your answer in this article(you can derived tabctrl and use from <ocde>WM_PAINT)

whitesky

double to CString and back

Desmo1619-Jul-06 0:29

Desmo16

19-Jul-06 0:29

Hi all,

I need to convert text from an edit control to double in an MFC application.
I also need to convert a double into a CString to display it in an edit box.

How can i do that ?

Thanx in advance,
Desmo16.

Re: double to CString and back

see me19-Jul-06 0:48

see me

19-Jul-06 0:48

You can use

For Double to CString
CString Format function

CString to Double
double atof(const char *string );

See msdn once before posting a question

Dream bigger... Do bigger...Expect smaller
aji

Re: double to CString and back

Roland Pibinger19-Jul-06 8:28

Roland Pibinger

19-Jul-06 8:28

Its meCString to Double
double atof(const char *string )

If you want error handling use strtod and check return value, errno and end-pointer. Frown | :(

Re: double to CString and back

Naveen19-Jul-06 0:48

Naveen

19-Jul-06 0:48

1.CString to double

use atof()

2. Double to CString.

use CString::Format() funtion.

nave

Re: double to CString and back

Ștefan-Mihai MOGA19-Jul-06 0:50

Ștefan-Mihai MOGA

19-Jul-06 0:50

You could use atof, _atof_l, _wtof, _wtof_l[^] functions for your own needs. Good luck and good day!

Re: double to CString and back

Hamid_RT19-Jul-06 2:37

Hamid_RT

19-Jul-06 2:37

See

<code>
char *Char; 
double Double;
   Char = " -1234.56";
   Double = atof( Char );
   CString str;
   str.Format("%lf",Double);

whitesky

Re: double to CString and back

Desmo1619-Jul-06 3:39

Desmo16

19-Jul-06 3:39

If i've got a char vector ( example: char name[30]),
and i want to convert it into a CString,
is there a way to do that ?

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