Re: IT WORKS!!! - C / C++ / MFC Discussion Boards

David Crow30-Jun-04 2:55

30-Jun-04 2:55

Avi Laviad wrote:
...but it throws me an exception. what should i do?!

How about telling us what the exception is, or maybe what the code looks like? It's hard to provide anything useful with the little bit of information you've provided.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Sorry...

JabraJabra30-Jun-04 3:00

JabraJabra

30-Jun-04 3:00

well, here is full detail of my code: (i hope)
in my CXXXApp::InitInstance() i did:

<br />
m_pConnection.CreateInstance(__uuidof(Connection)); //Create connection<br />
	try<br />
	{<br />
		m_pConnection->Open<br />
		("Provider=Microsoft.Jet.OLEDB.4.0;"<br />
		"Data Source=D:\\DATA\\Nwind.mdb", "", "", -1);<br />
<br />
	}<br />
	catch(_com_error *e)<br />
	{<br />
		CString Error = e->ErrorMessage();<br />
		AfxMessageBox(e->ErrorMessage());<br />
	}<br />
	catch(...)<br />
	{<br />
<br />
	}<br />

when i do this code in my View (it's MDI app) everything works fine.
when i do this - im getting into the catch(...).

is it making any sense to ya? Unsure | :~

Avi.

Re: Sorry...

David Crow30-Jun-04 3:04

David Crow

30-Jun-04 3:04

Avi Laviad wrote:
when i do this - im getting into the catch(...).

What message is displayed?

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Re: Sorry...

JabraJabra30-Jun-04 3:08

JabraJabra

30-Jun-04 3:08

no message, i don't have anything in the "catch(...)".
how can i know the message?
(sorry for my , i guess, stupied questions, im a newbie)..

Avi.

Re: Sorry...

David Crow30-Jun-04 3:22

David Crow

30-Jun-04 3:22

My bad.

I saw the one catch statement but not the other. I know of no way to ascertain the type/cause of exception at that point.

The last database application I did, the database object belonged to the document (as opposed to the app or the view). The document had methods for opening and closing the database connection.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Re: Sorry...

Jaime Stuardo30-Jun-04 3:45

Jaime Stuardo

30-Jun-04 3:45

Are you sure you called CoIninitialize(NULL) before CreateInstance call?

If you didn't call, you need to add that call before the CreateInstance and CoUninitialize() in ExitInstance function.

Jaime

IT WORKS!!!

JabraJabra30-Jun-04 21:21

JabraJabra

30-Jun-04 21:21

well thanks you very very much jaime!!!
thank you all for your patient.. Smile | :)

Avi

Re: IT WORKS!!!

Jaime Stuardo1-Jul-04 4:44

Jaime Stuardo

1-Jul-04 4:44

Some additional comments.

1.- Be sure CoInitialize is only called once in your application, and CoUninitialize is called just before shutting down the application.

2.- There was an easy way you could use to know which error occured. You know that CreateInstance returns an HRESULT. If after the call the pointer was 0x00000000, you can know the error by mean of the HRESULT (0 means no error).

For example, write the line this way:
HRESULT hr = ....CreateInstance(...);
or
TRACE("%x", ....CreateInstance(...));

Then copy the resulting code to the clipboard and finally, run the Error Lookup utility (present in Microsoft Visual Studio Tools menu). The copied error code will appear in Value edit box. Press Look Up button and the corresponding message will appear in Error Message window. For example, for your particular error, hr is 0x800401F0... using Error Lookup, you will get the message "CoInitialize has not been called".

Alternatively you can search that HRESULT code in winerror.h file.

Cheers
Jaime

Re: IT WORKS!!!

JabraJabra1-Jul-04 4:52

JabraJabra

1-Jul-04 4:52

wow!!
it's one of the help that i need to make as a Favourite Page.
10x man!

Avi. Blush | :O

Re: Sorry...

Antony M Kancidrowski30-Jun-04 6:01

Antony M Kancidrowski

30-Jun-04 6:01

Put a breakpoint on m_pConnection->Open line. Check to see if m_pConnection is not NULL and is valid.

If it isn't a _com_error it is more likely the pointer m_pConnection is invalid.

Ant.

I'm hard, yet soft.
I'm coloured, yet clear.
I'm fuity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Williams (Little Britain)

Re: Sorry...

JabraJabra30-Jun-04 21:11

JabraJabra

30-Jun-04 21:11

i did it before and the pointer m_pConnection was NULL (0x00000000).
i do it in the InitInstance of the MainApp.

but if i do it in the View, everything is OK.
... Confused | :confused:

global app pointer

JabraJabra30-Jun-04 1:52

JabraJabra

30-Jun-04 1:52

hi,
whats the name of the function that returns me the global application pointer?

Re: global app pointer

RChin30-Jun-04 2:08

RChin

30-Jun-04 2:08

If you are using MFC,
AfxGetApp().

I Dream of Absolute Zero

Tree Ctrl Refreshing

Manicka Vasagam N30-Jun-04 1:38

Manicka Vasagam N

30-Jun-04 1:38

I have 2 tree controls and when i drag an item form one tree control to another, the tree control doesnot get refreshed.
what should i do to avoid that D'Oh! | :doh:

Manickavasagam N
Software Engg. Consultant
ISRO Satellite Centre
Bangalore

Re: Tree Ctrl Refreshing

GermanGeorge1-Jul-04 2:07

GermanGeorge

1-Jul-04 2:07

did you try

m_tree.Invalidate(TRUE);

it works fine with me.

Help on dialog boxes!

cheenu_200230-Jun-04 1:14

cheenu_2002

30-Jun-04 1:14

I created a very simple dialog box with OK, CANCEL buttons on the top right hand corner of the dialog box. When I maximise the dialog box,these two buttons appear in the center of the dialog box. How can they be automatically positioned on the top right-hand corner of the enlarged window?
I am a beginner. Kindly help me out.

Srini

Re: Help on dialog boxes!

Johan Rosengren30-Jun-04 1:43

Johan Rosengren

30-Jun-04 1:43

1. You add control variables for the buttons.
2. You add a handler for the dialog WM_SIZE.
3. In this function, you test for the buttons being created (as WM_SIZE will be sent before the controls are created), for example so:

if( m_okButton.m_hWnd )
{
  //... rest of the code

4. If the buttons are created, you use the x and y inparameters to place and/or size the buttons as desired. The buttons can be moved with MoveWindow or SetWindowPos (the last one taking more parameters, but it can move without resize, for example).

Re: Help on dialog boxes!

User 665830-Jun-04 1:44

User 6658

30-Jun-04 1:44

Handle the WM_SIZING message (OnSizing() in MFC) and MoveWindow() your buttons according to the top-right corner.

regards

modified 12-Sep-18 21:01pm.

How to know if Oracle server connectivity is Okay?

mfc_surfer30-Jun-04 1:00

mfc_surfer

30-Jun-04 1:00

I need to monitor oracle server connection through run time and close the application as soon as the connection to oracle server is lost.
Any suggestion would be appreciated?
Please also let me know if you have a good idea for the monitoring than creating a thread?

Re: How to know if Oracle server connectivity is Okay?

Jaime Stuardo30-Jun-04 4:48

Jaime Stuardo

30-Jun-04 4:48

What oracle client version do you have? if it is 9xx.. have you installed OO4O?

Jaime

how to commnicate two pcs using usb

Member 120802930-Jun-04 0:21

Member 1208029

30-Jun-04 0:21

I have some data acqusition software in pc, This pc is acquireing data, I want send this data to another pc through USB. How I can Access USB driver?, What are the driver files? If some sample programme is there kindly send to me.
Regards,
subbu

Re: how to commnicate two pcs using usb

Henry miller30-Jun-04 2:59

Henry miller

30-Jun-04 2:59

USB wasn't designed for that, so you cannot do it without extra hardware. Best is to put an ethernet or 802.11 adaptor on USB, and use standard ip/sockets to comunicate.

Some companies make (or used to make) adaptors that would also do this. However I'm not sure extactly how they work, so I can't be sure they will provide you an interface to send data.

There is socket examples all over the internet, search them out.

how can i creat only one instance of my application

Anonymous29-Jun-04 23:45

Anonymous

29-Jun-04 23:45

hi,

I want to create only one instance of my application ,,
that only one instance run at a time on one PC.

any help or code plz

thanx

Re: how can i creat only one instance of my application

wb30-Jun-04 0:20

30-Jun-04 0:20

put a named mutex into the startup function...

Re: how can i creat only one instance of my application

Anonymous30-Jun-04 1:48

Anonymous

30-Jun-04 1:48

How can i use Mutex ..
Plz send code example i not know abut it
thanx

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