C / C++ / MFC

Re: Inhibe the ENTER and ESC KEYS ?

12-Apr-02 4:10

hmm, nice idea.

Mahdi Nejadsahebi10-Oct-12 11:21

Mahdi Nejadsahebi

10-Oct-12 11:21

you have to write and add these functions to your project:

void CMyproject::OnCancel(){
}

void CMyproject::OnOk(){
}

CRecordset and Oracle 8

12-Apr-02 3:49

I have created a simple VC Dialog based application and added a CRecordSet through the wizard over a table in the Oracle database using an ODBC connection.

The ODBC connection is fine cause the ODBC test for Oracle has verified it.

The problem is when I call

COracleRecSet recset;
recset.Open();

The application hangs Confused | :confused:

. Can anybody please tell what can be the problem.

wangyiming12-Apr-02 3:59

wangyiming

12-Apr-02 3:59

Maybe oracle only support open with:
CRecordset::forwardOnly

Alexandru Savescu12-Apr-02 4:54

Alexandru Savescu

12-Apr-02 4:54

Did you open a CDatabase object first to the database?
Something like :
CDatabase DB;
DB.OpenEx(...)

COracleRecSet recset (&DB);
recset.Open(...)

Best regards,
Alexandru Savescu

13-Apr-02 1:10

Is it necessary. I think for CRecordSet that was not necessary. But I tried that too.

Sorry same problem. Confused | :confused:

It hangs when calling recset.Open() Cry | :((

Alexandru Savescu13-Apr-02 2:20

Alexandru Savescu

13-Apr-02 2:20

Well I think it necessary. Try stepping into the MFC code and see where it hangs more specifically. There are a lot of reasons for which a Open will fail.
Good luck!

Best regards,
Alexandru Savescu

13-Apr-02 7:18

First of all thanks that you are taking interest in this.

I traced into the MFC recordset code. The database object gets allocated fine. The application hangs on the actual SC_ API call that connects to the oracle database.

Someone suggested that it can be the problem of the drivers. Can you comment...This problem is really bugging me.

bitmap display flicker

lucy12-Apr-02 3:33

12-Apr-02 3:33

I need to display a bitmap file at a rate of 10 frames per seconds or higher. I am using Chris' CDIBSectionLite. And here is my code for OnDraw:
HDC hdc = pDC->GetSafeHdc();
HDC hMemDc = CreateCompatibleDC(hdc);
HBITMAP hBmp = m_dib.GetSafeHandle(); // m_dib is an object of CDIBSectionLite
SelectObject(hMemDc, hBmp);
BitBlt(hdc, 0, 0, width, height, hMemDc, 0, 0, SRCCOPY);
DeleteDC(hMemDc);

but the display still flickers, not any better than a direct call to m_dib.Draw(pDC, ptDest, TRUE); or m_dib.Draw(pDC, ptDest, FALSE);

Am I missing anything? Confused | :confused:

Thank you very much in advance! Rose | [Rose]

C^hris L^osinger12-Apr-02 3:49

C^hris L^osinger

12-Apr-02 3:49

the problem is probably in your OnEraseBackground function. that function will clear the background between OnDraw calls. override it and return FALSE (or is it TRUE? anyway, return whichever says "i'll handle the background myself")

-c

Conscience is what hurts when everything else feels good.

Smaller Animals Software, Inc.

lucy12-Apr-02 3:56

12-Apr-02 3:56

Hi Chris, I've tried this. I overwrite BOOL CMainFrame::OnEraseBkgnd(CDC* pDC) , but no matter what I returned (TRUE or FALSE), I get the flicking problem all the same. Dead | X|

any clue?

Shog⁹12-Apr-02 4:50

Shog⁹

12-Apr-02 4:50

lucy wrote:
I overwrite BOOL CMainFrame::OnEraseBkgnd(CDC* pDC)

You also have a view though, right? How about implementing OnEraseBkgnd() for the view?

Developers that like shiny objects also dig case mods and scratch-and-sniff stickers.

Klaus Probst, The Lounge

lucy12-Apr-02 4:58

12-Apr-02 4:58

Ah I got it. At first I thought the WM_ERASEBKGND can only be handled by the frameWnd since I couldn't find it in classWizard for the view. After reading your advice, I overwrite the view's WindowProc and check for this message, then overwrite it based on my program requirement. now the bitmap is shown perfectly.
Thank both of you a lot! Rose | [Rose]

lucy12-Apr-02 5:27

12-Apr-02 5:27

sorry, one more question:

I am updating the display using a bitmap file at a rate of 10 frames per second in a worker thread, when I need to overwrite the process of WM_ERASEBKGND. At the same time, I want to respond to user event, like file open.

The problem is: if my worker thread is running and the background is not erased, there would be funny things left on the display, like the file open dialog even after the dialog is closed. How do I know the WM_ERASEBKGND is posted by the worker thread and when it is posted by other UI thread so that I can treat it differentely in my view?

Thanks a lot!

Shog⁹12-Apr-02 6:02

Shog⁹

12-Apr-02 6:02

Sorry if i missunderstand your question, but:

You should not be posting WM_ERASEBKGND directly. Use Invalidate(), do nothing in OnEraseBkgnd(), and draw the bitmap in OnPaint(). That way, whenever the frame changes, you'll invalidate and the window will repaint. And, when the window is invalidated for some other reason (window is uncovered, menu disappears, etc.) the window will also repaint correctly.

Developers that like shiny objects also dig case mods and scratch-and-sniff stickers.

Klaus Probst, The Lounge

lucy12-Apr-02 6:36

12-Apr-02 6:36

yeah, I think I am doing this. the pseudo code is :

CMainFrame::OnImage()
{
  AfxBeginThread(BitmapUpdate, pMyView);
}

UINT BitmapUpdate(LPVOID pParam)
{
  m_bImage = true;
  while(m_bImage)
  {
    // update CDIBSectionLite ten times per second
    pMyView->Invalidate();  
  }
}

CMyView:: OnDraw()
{
  // use memory dc to avoid flickering
}

CMyView::WindowProc(....)
{
  if ( message == WM_ERASEBKGND && m_bImage )
     return TRUE;
}

but when m_bImage is true, when my bitmap cannot cover the whole client area, background outside my bitmap area will not be updated until I clear m_bImage. What should I do?
Confused | :confused:

Shog⁹12-Apr-02 8:31

Shog⁹

12-Apr-02 8:31

If you know what area the bitmap takes up, just erase the borders around that area before returning on WM_ERASEBKGND. BTW, you should be able to use CMyView::OnEraseBkgnd() instead of CMyView::WindowProc().

As a side note:
kilowatt has written several very nice articles on these subjects you may want to read; i would especially recommend you read Guide to WIN32 Paint for Intermediates and A Guide to WIN32 Clipping Regions as they are both very relevant to what you are trying to accomplish.

Developers that like shiny objects also dig case mods and scratch-and-sniff stickers.

Klaus Probst, The Lounge

lucy12-Apr-02 9:18

MFC: Doc/View update sequence?

12-Apr-02 9:18

Thank you. I am reading those articles.

12-Apr-02 2:17

Hello,

I'm a games programmer and I'm writing a level editor using MFC for putting game objects in our levels. I've got an SDI document/view MFC project and I'm using a splitter window to split the framework into a treeview (for the game data) and an OpenGL view (to view the level geometry and visual representation of the game data).

The question I need answering is: at what point after loading data can I fill the Treeview? I need to remove all treeviews items when I load a new set of game data so I was originally doing this in CTreeView::OnInitialUpdate() using TreeCtrl::DeletAllItems(). But when I load my data from CDocument::OnOpenDocument() I want to fill in the data in the view using UpdateAllViews(). OnInitalUpdate() gets called after OnOpenDocument and hence deletes all the data I've added so at what point do I fill in the data in my treeview?

Can anyone explain a good way (or the correct way!) to do this please?

Thanks,
Marc

Ravi Bhavnani12-Apr-02 2:36

Ravi Bhavnani

12-Apr-02 2:36

Marc Littlemore wrote:
I want to fill in the data in the view using UpdateAllViews().

That seems the right thing to do. In which case, I think you want to update the contents of the tree in your view's OnUpdate() method.

/ravi

"There is always one more bug..."
http://www.ravib.com
ravib@ravib.com

12-Apr-02 2:42

Ravi - yes, that's what I'm currently doing _but_ it calls OnInitalUpdate _after_ I call OnUpdate (via UpdateAllViews() in the document). So what's happening is that I'm filling in my treeview after loading (from OnOpenDocument() in CDocument) and then at some point afterwards it calls OnInitialUpdate() which is where I was removing all previous data.

Is there a specific place which I should initialise my treeview from other than OnInitialUpdate(). If not, how do I get around my problem?

Thanks,
Marc

Ravi Bhavnani12-Apr-02 3:00

Ravi Bhavnani

12-Apr-02 3:00

Hmmm, a couple of thoughts:

OnInitialUpdate() should not be called automatically when you call UpdateAllViews(). Are you manually calling OnInitialUpdate()? (If so, you shouldn't.)
How about removing old data from the tree control in OnUpdate() (instead of OnInitialUpdate()) just before you load new data?

/ravi

"There is always one more bug..."
http://www.ravib.com
ravib@ravib.com

12-Apr-02 2:57

OnInitialUpdate is called (according to MSDN) after the view is first attached to the document. This is done via OnUpdate() (with a default hints of 0 for both parameters). I'm not calling it.

I'll try removing the data via OnUpdate(). Sounds like a great idea!

Thanks,
Marc

Ravi Bhavnani12-Apr-02 3:12

Ravi Bhavnani

12-Apr-02 3:12

Marc Littlemore wrote:
This is done via OnUpdate()...

Not quite! OnInitialUpdate() ends up calling OnUpdate(), not the other way around. OnInitialUpdate() should only contain one-time initialization code. I think things should work properly when you empty the tree control in OnUpdate().

/ravi

"There is always one more bug..."
http://www.ravib.com
ravib@ravib.com