C / C++ / MFC

Re: can u use HRESULT_CODE in VC's tool "Error Lookup"?

19-Nov-02 20:57

can u use HRESULT_CODE in VC's tool "Error Lookup"?

norm

Gary R. Wheeler20-Nov-02 14:08

Gary R. Wheeler

20-Nov-02 14:08

Yes. The ErrLook.Exe program is a simple little wrapper around the FormatMessage() API function. As a result, any error code that it can recognize, the ErrLook program can display. Note that not all HRESULT's have messages, which is why some of them don't display anything.

Software Zen: delete this;

exception for ADO recordset open method

devvvy19-Nov-02 18:37

19-Nov-02 18:37

hi, writing a win32 console app that doesnt support MFC (besides CDBException is for ODBC ..)

i opened a recordset and since the open method doesnt return a HRESULT, i need to use try-catch mechanism.

but how?

try
{
pRs->Open(....);

}

catch( what?)
{

}

Reference:

recordset.Open Source, ActiveConnection, CursorType, LockType, Options

(Note: No return value)

thanks gurus!

norm

Christian Graus19-Nov-02 19:39

19-Nov-02 19:39

if you catch (...), you'll catch all exceptions. There is a com_exception, or similar, but I forget exactly what it's called.

Christian

No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002

Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002

Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002

devvvy19-Nov-02 19:44

19-Nov-02 19:44

just found out...

try
{
pRs->Open(vNull, vNull, adOpenForwardOnly, adLockReadOnly, adCmdUnknown);
}
catch(_com_error &e)
{
//Additional error handling here.
cout << "ERROR: Failed to open recordset." << endl;
cout << "ERROR msg: " << e.ErrorMessage() << endl;
}

But the error msg is soooo vague:

Unknown error 0x800A0E79

I'm banging my head against my cactus but apparently it doesnt help

norm

Christian Graus19-Nov-02 19:48

19-Nov-02 19:48

In the tools menu of VC is an error number checker. Put this number into it and it will pop up a dialog that says 'error message not found'. Or, 1 in 1,000 times, it knows what this HRESULT means, and then it tells you Smile | :)

Christian

No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002

Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002

Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002

devvvy19-Nov-02 20:06

19-Nov-02 20:06

tried, it says cant find the message ("Message not found") with "0x800A0e79"..

the tool is called "Error Lookup"

catch(_com_error &e)
{
//Additional error handling here.
cout << "ERROR: Failed to open recordset." << endl;
cout << "ERROR: e.ErrorMessage(): " << e.ErrorMessage() << endl;

hr = e.Error();
cout << "ERROR: HRESULT_CODE( e.Error() ): " << HRESULT_CODE(hr) << endl;
}

But if Error Lookup HRESULT_CODE(hr)==3705 gives the following msg "Bad or missing LAN Manager root directory." --- this doesnt make a lot of sense coz it's a local SQL server and previous statements all executed with good HRESULT==S_OK

norm

devvvy19-Nov-02 20:07

how can u enumerate tables given a database?

19-Nov-02 20:07

sorry, for error = 3705, Error Lookup yeilds "Message Not Found"

oops

norm

devvvy19-Nov-02 17:12

19-Nov-02 17:12

how can u enumerate tables given a database?

btw, we use ADO for database access. and we use SQL server.

thanks!

norm

Christian Graus19-Nov-02 17:22

19-Nov-02 17:22

Read my article called MSDEGUI - the queries I use there should work for you. It's in the new list on the main page.

No, I don't remember them, or I'd just tell you Smile | :)

devvvy19-Nov-02 17:34

19-Nov-02 17:34

just scan yr article briefly. isnt it for .NET?

anyway, i'm building all my code with VC6 - lots of anti microsoft types here in this company.

anyway, i am thinking, perhaps I can read MyDB.Tables.sysobjects

there're three columns of interests:

a. "names" -- object name: a simple string

b. "id" -- object id: just a simple integer

c. "xtype" and code as follows:

Object type. Can be one of these object types:
C = CHECK constraint
D = Default or DEFAULT constraint
F = FOREIGN KEY constraint
L = Log
FN = Scalar function
IF = Inlined table-function
P = Stored procedure
PK = PRIMARY KEY constraint (type is K)
RF = Replication filter stored procedure
S = System table
TF = Table function
TR = Trigger
U = User table
UQ = UNIQUE constraint (type is K)
V = View
X = Extended stored procedure

So, I will just count and retrieve an array of names (names - column one of sysobjects table) for all entries where xtype==U

norm

Christian Graus19-Nov-02 17:47

19-Nov-02 17:47

norm wrote:
just scan yr article briefly. isnt it for .NET?

Yes, so ? The query remains the same, all that changes is the layer that is talking to SQL Server.

norm wrote:
anyway, i'm building all my code with VC6 - lots of anti microsoft types here in this company.

Has no-one told them it comes from Microsoft ? :P

norm wrote:
anyway, i am thinking, perhaps I can read MyDB.Tables.sysobjects

I suspect that is exactly what I did in the article I pointed you to.

Christian

No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002

Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002

Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002

devvvy19-Nov-02 18:16

19-Nov-02 18:16

thanks chris. and i hope that there'll be a day when it's no longer hip just being an anti microsoft. it's so stupid.

norm

Christian Graus19-Nov-02 18:17

19-Nov-02 18:17

If that day comes, it will be the day after Solaris penetrates 90% of the market.

Christian

No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002

Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002

Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002

devvvy19-Nov-02 18:21

19-Nov-02 18:21

just remember in addition to cursor type, u can also specify whether you want server side cursor or client side cursor isnt it?

can u tell me where I should read up in this regard?

norm

Christian Graus19-Nov-02 19:41

19-Nov-02 19:41

Dunno, a book on ADO ? O'Reilley have a good one, from memory.

Christian

No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002

Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002

Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002

Detect CEdit number of lines?

RichardGrimmer19-Nov-02 22:01

RichardGrimmer

19-Nov-02 22:01

Simple solution - use OpenSchema method of ADO Connection object:

pConn->OpenSchema(adSchemaTables,vParams)

where vParams is a Safearray containing the following null, schema_name, null, null. This then returns a recordset which contains all of the tables in the schema. To enumerate the fields of a table, use similar:

m_pConn->OpenSchema(adSchemaColumns, vParams)

where vParams contains null, schema_name, table_name, null. Again returns recordset that can be used to get all sorts of information.

If you need a fuller example, fell free to e-mail me. vParams cna be used to control the operation in a much more detailed way than here, but this provides basic naming information.Also, has the advantage that will work with any DB type (SQLServer, Oracle, Access etc).

Hope it helps

Anonymous19-Nov-02 16:40

19-Nov-02 16:40

Hi, I have an CEdit control which can be resized. The user can switch from a single line edit control to a multi line control if he decides so.

How do I detect the number of lines (a CEdit can hold not actually has)? I need to catch the switch from a single - to multi line layout and change some atributes.

Thanks

Anonymous19-Nov-02 19:38

19-Nov-02 19:38

someone with a hint?

Roger Allen20-Nov-02 2:49

Roger Allen

20-Nov-02 2:49

Do you mean visible lines in the edit control? There is no limit to the number of lines a control can have upto the 64K byte limit of \r\n pairs 63336/2 = 32768 possible lines held.

If its just the number of lines the control could display without a scrollbar, then you can compute this by gettting the client area size of the control, the DC and the font, and then count the number of lines like this:

int ComputeLines(int ID)
{
CWnd *pWnd = GetDlgItem(ID) ;
if (!pWnd)
return 0;

CEdit *pEdit = static_cast<CEdit*>(pWnd);
if (!pEdit)
return 0 ;

CDC *pDC = pEdit->GetDC() ;
CFont *pFont = pEdit->GetFont();

CFont *pOldFont = pDC->SelectObject(pFont);
CRect rect ;

pEdit->GetCLientRect(&rect);
CSize size = pDC->GetTextExtent("A", 1);
pDC->SelectObject(pOldFont);
ReleaseDC(pDC);
return rect.Height() / size.cy;
}

OK, the above it untested and types directly so, it may, may not work correctly

Roger Allen
Sonork 100.10016

I have a terminal disease. Its called life!

Anonymous20-Nov-02 20:35

20-Nov-02 20:35

Roger Allen wrote:
If its just the number of lines the control could display without a scrollbar, then you can compute this by gettting the client area size of the control, the DC and the font, and then count the number of lines like this:

thousand thanks, Roger! Cool | :cool:

Anonymous20-Nov-02 20:38

very good samples on connection string format

20-Nov-02 20:38

PS: instead of GetDC/ReleaseDC I might better use a CClientDC(this), which is an MFC encapsulation of this AFAIK.

devvvy19-Nov-02 15:44