C / C++ / MFC Discussion Boards

Re: Why...

Nish Nishant15-Jul-02 14:56

Nish Nishant

15-Jul-02 14:56

bConnected never becomes TRUE I'd guess.
Perhaps this if nevere succeeds :-
if (sInput.Find("connect") != -1)

Nish

Author of the romantic comedy

Summer Love and Some more Cricket [New Win]

Review by Shog⁹
Click here for review[NW]

Getting RuntimeClass of a CObject Derived Class

MightyThor15-Jul-02 12:16

MightyThor

15-Jul-02 12:16

Hi,

i have 3 objects derived from CObject.
These objects are the data source for my tree control. I want to find out which object is selected so i tried to use RUNTIME_CLASS macro.

CObject *selectedItem = ( CObject * ) m_treeMain.GetItemData( m_treeMain.GetSelectedItem() );

if( selectedItem )
{
if( selectedItem->IsKindOf( RUNTIME_CLASS( CBand ) ) )
{
AfxMessageBox( "so far so good" );
}
}

This code causes two errors :

1) error C2039: 'classCBand' : is not a member of 'CBand'
2) error C2065: 'classCBand' : undeclared identifier

What is this classCBand anyway?
I included Band.h into this function's file. And when i replace CBand with another class name such as CObject or CTreeCtrl, it works. So what's wrong with my class? What should i do to retrieve the runtime class ?

Thanks in advance.

Re: Getting RuntimeClass of a CObject Derived Class

Christian Graus15-Jul-02 12:34

Christian Graus

15-Jul-02 12:34

There is a macro you need to include in your class for this stuff to be declared. I was forced to use this crap by a former employer, it is at best a hack. You should instead use dynamic_cast, which works for anything, not just CObject derived stuff.

CBand *selectedItem = dynamic_cast<CBand*>( m_treeMain.GetItemData( m_treeMain.GetSelectedItem() ));

if( selectedItem )
{
   AfxMessageBox( "so far so good" );
}

dynamic_cast returns NULL if the cast is invalid, otherwise the object requested. It also tells you at compile time if the cast you are attempting is unreasonable.

Christian

come on all you MS suckups, defend your sugar-daddy now. - Chris Losinger - 11/07/2002

Re: Getting RuntimeClass of a CObject Derived Class

Roman Fadeyev15-Jul-02 19:03

Roman Fadeyev

15-Jul-02 19:03

If you use dynamic_cast, check up option "Enable Run-Time type info" in your project settings. It is switched off by default, AFAIK

Re: Getting RuntimeClass of a CObject Derived Class

Christian Graus15-Jul-02 19:13

Christian Graus

15-Jul-02 19:13

That is true. I forgot that one, sorry. Blush | :O

Christian

come on all you MS suckups, defend your sugar-daddy now. - Chris Losinger - 11/07/2002

Re: Getting RuntimeClass of a CObject Derived Class

MightyThor15-Jul-02 23:35

MightyThor

15-Jul-02 23:35

Thank you both for your help. It's working fine now.
But i had to do a minor change in your code sample.

CBand *selectedItem = dynamic_cast<cband*>( (CObject*)
m_treeMain.GetItemData(
m_treeMain.GetSelectedItem() ));

if( selectedItem )
{
AfxMessageBox( selectedItem->GetBandName() );
}

I don't know why but it didn't directly cast from DWORD to CBand and gave the following message :

error C2681: 'unsigned long' : invalid expression type for dynamic_cast

So i decided to cast it to CObject* first. Frankly, i didn't quite understand why this change made it work, but it did, so i just moved on

Anyway, thanks again. Cool | :cool:

excel automation, hprocess is not closing

pnpfriend15-Jul-02 12:10

pnpfriend

15-Jul-02 12:10

hi all,
I found an article about I have an excel automation dos based application . I take an article,
Automate excel from c++ without using mfc or #import (Q216686) as an example.

then based on another article Automate excel and then know the use closed it(Q192348)
I changed my code again. actually, i added,

<br />
// wait until the user close the application<br />
<br />
    HWND hWnd;<br />
    char buf[1024];<br />
    hWnd = ::FindWindow("XLMain",NULL);<br />
    if(NULL==hWnd)<br />
    {<br />
      long lErr = GetLastError();<br />
      sprintf(buf, "FindWindow Error code = %d",lErr);<br />
      AfxMessageBox(buf);<br />
    }<br />
    <br />
    DWORD pid;<br />
    DWORD dThread;<br />
    DWORD dwReason;<br />
    dThread = ::GetWindowThreadProcessId(hWnd,&pid);<br />
    HANDLE hProcess;<br />
    hProcess = ::OpenProcess(SYNCHRONIZE|PROCESS_ALL_ACCESS,TRUE,pid);<br />
<br />
    dwReason = ::WaitForSingleObject(hProcess,INFINITE);<br />
    ::CloseHandle(hProcess);<br />

everything is fine except
dwReason = ::WaitForSingleObject(hProcess,INFINITE);
is waiting forever because in windows task manager's processes tab, you will find EXCEL.EXE eventhough you have closed ms excel application.

if you command the line
dwReason = ::WaitForSingleObject(hProcess,INFINITE);
you will not find EXCEL.EXE in windows task manager's processes tab.
why is that?

please......

pnpfriend16-Jul-02 2:44

pnpfriend

16-Jul-02 2:44

can someone help me please Cry | :((

Re: excel automation, hprocess is not closing

Richard Ellis16-Jul-02 14:05

Richard Ellis

16-Jul-02 14:05

G'Day Win,

I use the same code successfully. What I discovered was that as I developed the application I would run it and terminate it prematurely with Excel open. This of course did not close down excel properly. So that when I started the application again I had 2 versions of excel running etc. Thus when I had a 'real' excel application running and I tested my program and shut excel down this code failed because I had closed down a different excel to the one being watched. I think this is what may be happening in your case. So terminate all excel processes with task manager, run excel and then your application and see if it works then.

Hope that is of some help,

Richard.

Re: excel automation, hprocess is not closing

pnpfriend17-Jul-02 3:39

pnpfriend

17-Jul-02 3:39

thank you Richard.
that's is a really helpful. Thanks

derive a class from my tree control

Steve L.15-Jul-02 11:39

Steve L.

15-Jul-02 11:39

I need to handle the WM_MOUSEMOVE message for my tree control. I've been told that I have to derive a class from my tree control and handle mousemove int there but I can't figure out how to derive the class from my tree control.

-Raffi

Re: derive a class from my tree control

Joaquín M López Muñoz15-Jul-02 11:43

Joaquín M López Muñoz

15-Jul-02 11:43

It's simple. Launch the MFC wizard (CTRL+W) and create a new class selecting CTreeCtrl as the base class (call it CMyTreeCtrl, for instance.) Handle WM_MOUSEMOVE in the new class. Now, where you defined a variable of type CTreeCtrl, replace CTreeCtrl with CMyTreeCtrl (you'll need to include "mytreectrl.h", also.) That's it.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Re: derive a class from my tree control

Steve L.15-Jul-02 11:50

Steve L.

15-Jul-02 11:50

I previously have all my tree control code in my view class. Do I have to move all my tree control code to this new class or will it work with just leaving it as is and doing what you said above?

-Raffi

Re: derive a class from my tree control

Joaquín M López Muñoz15-Jul-02 12:01

Joaquín M López Muñoz

15-Jul-02 12:01

It'll work by only replacing CTreeCtrl with the new class, you can leave all the other stuff where it was

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Re: derive a class from my tree control

Steve L.15-Jul-02 12:08

Steve L.

15-Jul-02 12:08

worked perfectly, thanks a lot Smile | :)

-Raffi

Using CRecordset

achandra00715-Jul-02 10:23

achandra007

15-Jul-02 10:23

Hi All

I am trying to connect to SQL Server using the ODBC classes. In my sql to CRecordset.Open, I provide a query which looks like:

CString sSql = "select ani from cxcu where company = ' + sCompany;

cxcu is a very large table and the query will return upward of 600k records. I am also turning on the CRecordset::useMultiRowFetch option.

What I want to do is to lookup an "ani" ( from above query ) and check if it exists in the table or not.

Would it make sense if I connected with a NULL string and then called Requery()? I am having to wait for a very long time (in excess of 15 minutes) for the CRecordset.Open(...) to complete.

What would be the best way to do this lookup of a record in amongst 600k+ using CRecordset?

Thanks
ashish

Re: Using CRecordset

Ranjan Banerji15-Jul-02 11:02

Ranjan Banerji

15-Jul-02 11:02

Have you investigated as to how long will it take for the query to execute from QueryAnalyzer in SQlServer itself? If not you may want to do that and then see what type of indexing may be required to make your query go faster.

If the existing WHERE clause is returning 600K plus records and you wish to run this query only to see if this company exists then try to tighten the WHERE clause such that the number of records returned is smaller.

Re: Using CRecordset

achandra00715-Jul-02 11:39

achandra007

15-Jul-02 11:39

Thanks Ranjan. Here is what I am currently doing:

Since the lookup has to be from a table with 600k+ records, I have to load it using CRecordset.Open. This would take me upwards of 10-15 minutes.

Now, to avoid this, what I am having to do is to call CRecordset.Open and CRecordset.Close to check each input value.

So what I am doing is setting the SQL and m_strFilter for each check I am performing. I am lucky that the field "ani" is indexed in the database.

Surely there is better way to do this????

thanks
ashish

ComboBoxEx with DropList style problem

Maciek Niedzielski15-Jul-02 10:10

Maciek Niedzielski

15-Jul-02 10:10

I've just started learning VisualC++. I'm using Ivor Horton's book "Introduction to MS VisualC++ Standard Edition". I'm in chapter "MFC Dialog Programming".
I have a problem with a ComboBoxEx.
I put it on a form and add a member variable for it (Variable type is set to Value) m_strCboEx. Then, I add several items to the item-list.
At this stage, everything is working as I expected - whatever I choose in a running program it goes to m_strCboEx.
However, when I change combo's style to DropList - m_strCboEx is always an empy string at the end.
Why is it so?
I tried to use standard ComboBox instead of ComboBoxEx and in this case everything was OK.
I don't understand... Confused | :confused:

Can you help me?

Maciek Niedzielski

How to make invisible CEdit visisble with code?

ns15-Jul-02 10:09

15-Jul-02 10:09

I have a CEdit control on a CFormView (didnt create it in code). I set its visible property to invisble. Now I want it to show up at runtime under certain conditions. How do I do this? Says Visible(TRUE) is not a property of Cedit....

Thanks,
Ns

nevermind - I got it!

ns15-Jul-02 10:15

15-Jul-02 10:15

OOps! It was ShowWindow(SW_SHOW).
Thanks anywyas,
ns

Opening a serial COM port

dorin15-Jul-02 9:47

dorin

15-Jul-02 9:47

If anyone could help me with this I'd appreciate it.....

I've been trying to find out how to open a serial COM port through Visual C++ 6.0. Laugh | :laugh:

There is a sample code at http://www.codeproject.com/managedcpp/howtocomport.asp , but it doesn't work in Visual C++...

does anyone know what changes I have to make??

Re: Opening a serial COM port

Joaquín M López Muñoz15-Jul-02 9:58

Joaquín M López Muñoz

15-Jul-02 9:58

//Opens COM1
HANDLE hPort=CreateFile(
  "\\\\.\\COM1",GENERIC_READ|GENERIC_WRITE,0,NULL,
  OPEN_EXISTING,0,NULL);

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Weird Acception Violation :: MFC

valikac15-Jul-02 9:35

valikac

15-Jul-02 9:35

Hi.

I have discovered a major bug in a simple program. The problem has a propertysheet. There are two pages the are almost exactly the same. Both pages have a CListCtrl box. In both pages, the user can add items, select items, and/or remove existing items.

For some reason, only one page worked in the *release* version of the program. Everything worked perfect in debug mode, but one page crashed in release. The page that crashed does so in the same manner every time. Below is a logs of the crash.

// debug log

-----
// this occurs AFTER the user options a propertysheet
// program does NOT crash at this point

First-chance exception at 0x7196254a in myProgram: 0xC0000005: Access violation writing location 0x00463b2c.

// this occurs when the user selects an item in a CListCtrl box
// program crashes at this point

First-chance exception at 0x046936d7 in myProgram: 0xC0000005: Access violation reading location 0x046936d7.

Unhandled exception at 0x046936d7 in myProgram: 0xC0000005: Access violation reading location 0x046936d7.

The program '[1120] myProgram: Native' has exited with code 128 (0x80).
-----

I have no idea how to fix this problem. I have compared the two property pages I mentioned that have the CListCtrl boxes. The code in both property pages are flawless.

First, I thought the program crashed because there was a code program in the function that determines what item is selected in the CListCtrl box. However, I have found that the program does not crash at all inside that function. It crashed sometime after leaving the function.

Is this a memory problem? Please post if you have any idea on debugging this problem.

Thanks,
Kuphryn

Re: Weird Acception Violation :: MFC

Joaquín M López Muñoz15-Jul-02 9:50

Joaquín M López Muñoz

15-Jul-02 9:50

Unless there's someone else here with strong divination capabilities, a little more help from you would be great. It could have to do with the data you're using to feed the controls (uninitialized arrays or something.) You can also take a poor-man approach to release mode debugging plaguing your code with MessageBoxes and try to determine the exact location where the error is happening.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

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