|
|
Hi Folks
Re: ADO.NET : SqlDataReader : I need to assign retrieved value to C++ variable
I have found the source of the problem expressed in the thread "ADO.NET : SqlDataReader : I need to assign retrieved value to C++ variable":
http://www.codeproject.com/script/comments/forums.asp?forumid=3785#xx309754xx
but do not yet know why it occurs or how I can fix it.
The problem arises with the /clr compiler setting.
Here is the code to illustrate this:
/////////////////////////////////////////////////////////
#include <stdafx.h>
#include <cstdlib>
#include "try_ADONET.h"
//#using <mscorlib.dll>
//#using <system.dll>
//#using <system.data.dll> // This is required for the ADO.NET Provider
using namespace std;
//using namespace System;
int Main()
{
CString busNumberSQL[2];
CString bus = "Hello";
busNumberSQL[1] = bus;
return 0;
}
////////////////////////////////////////////////////////
Without the /clr setting the array of CString busNumberSQL[2] is correctly contructed as is CString bus and the line
busNumberSQL[1] = bus;
works as expected. This can be seen by putting a breakpoint in at
return 0;
and seeing the variables in a Watch. Copy the expanded Watch details (Name, Value & Type) to an EXCEL sheet.
..................
Next, add the compiler switch /clr and rerun the code.
CString bus is constructed correctly BUT something weird happens in the construction of CString busNumberSQL[2].
Now,
busNumberSQL[1] = bus;
results in the address of bus as an integer being assigned to busNumberSQL[1], and look at the Watch details!!
Copy the expanded Watch details (Name, Value & Type) to an EXCEL sheet
Name: busNumberSQL; Value: {Length=2}; Type: ATL::CStringT<char,strtraitmfc<char,atl::chtraitscrt<char> > >[] ...(Note no dimension at end compared to the "no /clr" case.
Next Watch line: [0] 2083454756 __int32
Next Watch line: [1] 3103464 __int32
My conclusion is that busNumberSQL[2] is not an array of CString.
Of course, I need the /clr in order to use ADO.NET!
It seems as though a CString works, but a CString array for some (unknown) cannot even be defined.
Do you have any light for me? (I have not got into your previous post yet on Marshall)
Best regards
Doug.
(In case you are wondering I am very much a beginner with C++ and .NET)
Doug
|
|
|
|
|
Doug, I've noticed that you've posted this in several forums. In general, everywhere on the net(especially here on CP), what you are doing, which is known as cross-posting, is frowned upon. Please post a certain question only once. I know that your question deals with .NET/ADO.NET/C++.NET, but please post it in the C++ forum because that's what you are truly dealing with in your problem. Just wanted to give you a friendly reminder of posting-etiquette.  Especially because some people can get a little harsh about this.
As an aside, welcome to CP and the development community.
Norm Almond: I seen some GUI's in my life but WTF is this mess 
Leppie: I made an app for my sister and she wouldnt use it till it was colorful enough
Norm:good point leppie, from that statement I can only deduce that this GUI must be aimed at children
Leppie:My sister is 25
-Norm on the MailMagic GUI
|
|
|
|
|
David
Thank-you for informing me of this posting-etiquette, of which I was ignorant, and to which I will adhere in future.
I'll make a suggestion that forum etiquette/rules be expressed somewhere on the CP site.
Is the reason for this etiquette to avoid consuming too much computer real estate?
How does one ensure that one is "heard" by as many members as possible who may have the requisite knowledge to advise, but who may normally only browse in one particular forum?
Regards
Doug
Doug
|
|
|
|
|
Doug wrote:
Is the reason for this etiquette to avoid consuming too much computer real estate?
Not really.(Although Chris might tell you differently) The problem is that when you cross-post, people see all of them and it just gets annoying. I think that the best way to get people to see your post is just to post it in the VC++ forum. So many people are in that forum and a lot of them have dealt with Databases and ADO.NET before, so you may just want to post it there. Especially since your problem dealt more with C++ than with ADO.NET.
Norm Almond: I seen some GUI's in my life but WTF is this mess
Leppie: I made an app for my sister and she wouldnt use it till it was colorful enough
Norm:good point leppie, from that statement I can only deduce that this GUI must be aimed at children
Leppie:My sister is 25
-Norm on the MailMagic GUI
|
|
|
|
|
Another thing I noticed that I didn't quite respond to:
Doug wrote:
but who may normally only browse in one particular forum?
Believe me Doug, CP becomes an addiction, and if you start spending any amount of time on here, you will find this to be true: Nobody only visits one forum.  For instance, I regularly visit The Lounge, The Soapbox, the C# forum, the .NET Framework forum, and the new ASP.NET forum. Along with the others that I frequent less regularly such as the ADO.NET forum and the general Web Development forum. So really, you will probably catch the same amount of people. And if you've posted in the wrong forum (Don't ever post a programming question in the Lounge. You'll be unmercifully slaughtered), people will tell you where you should put your question or direct you to a specific person who may be able to answer it.
Norm Almond: I seen some GUI's in my life but WTF is this mess
Leppie: I made an app for my sister and she wouldnt use it till it was colorful enough
Norm:good point leppie, from that statement I can only deduce that this GUI must be aimed at children
Leppie:My sister is 25
-Norm on the MailMagic GUI
|
|
|
|
|
Doug,
Despite what David has said, I find the biggest problem with cross-posting is that it's really annoying when you spend time answering someone in one forum and then find that someone else has already given them the exact same answer somewhere else.
It's usually fair to say that people will visit every forum that applies to them and most questions do fall quite heavily into one category - yours for example is clearly of no interest to people who don't look at ADO.NET, despite the fact that it has C++ connections.
[EDIT]What the hell was I thinking about here? This sentence should have read "people who don't look at MC++, despite the fact that it has ADO.NET connections"!!![/EDIT]
If you do find that you don't get a response in the obvious forum and you start thinking you might have done better elsewhere, post a message in the other forum saying "Please take a look at this question in the ADO.NET forum:" and offering a link to the original message. That will usually draw a lot less scorn than cross posting.
David's suggestion that it's a good idea to post in the C++ forum because most people go there is a strange one.
For one thing, I'd imagine an MC++/ADO.NET question like yours would draw a few complaints in the C++ forum. For another, contrary to popular opinion, some people don't visit the C++ forum very often.
I for one find that I can't offer a lot of help there so I usually only go there when I want to ask a question. I make up for it by answering questions in the C# and Web Dev forums where I know a little bit more
Paul
Life is just a sexually transmitted desease - Matthew Wright (ex-journalist, TV presenter) 10-Oct-02
I finally have a sig! - Paul Riley (part-time deity) 10-Oct-02
|
|
|
|
|
Thanx Paul
Good points well made and taken to heart.
regards
Doug
Doug
|
|
|
|
|
Paul Riley wrote:
David's suggestion that it's a good idea to post in the C++ forum because most people go there is a strange one.
Argh! I meant the MC++ forum. Sorry about that...
Norm Almond: I seen some GUI's in my life but WTF is this mess
Leppie: I made an app for my sister and she wouldnt use it till it was colorful enough
Norm:good point leppie, from that statement I can only deduce that this GUI must be aimed at children
Leppie:My sister is 25
-Norm on the MailMagic GUI
|
|
|
|
|
hello,
i've got an application totally developed using .NET, and i'm about to embark on see if it'll run on a Mac machine.
is this possible?? has anyone out there attempted this? if so, and successfully, is there anything in particular i need to know or do??
thank you
Orion
orion.buttigieg@Teamplate.com
www.Teamplate.com
|
|
|
|
|
You are probably not working for a real world project, do you ?
She's so dirty, she threw a boomerang and it wouldn't even come back.
|
|
|
|
|
How blunt of you...
Norm Almond: I seen some GUI's in my life but WTF is this mess
Leppie: I made an app for my sister and she wouldnt use it till it was colorful enough
Norm:good point leppie, from that statement I can only deduce that this GUI must be aimed at children
Leppie:My sister is 25
-Norm on the MailMagic GUI
|
|
|
|
|
Unfortunately you need the .net framework in order to run apps. The framework has not been ported to the Mac. However, the framework is currently being ported to Linux via www.go-mono.com project which is rumoured to be porting it to the mac once they finsh. I've also heard that Corel was working on this for the Mac but who knows. Anyway, your app will not run.
|
|
|
|
|
ez2,
thanks for the reply. i know i need the framework to run the .NET i just wasn't sure if the .NET would like the Mac OS. i didn't think it would but you never know there might have been a work around somewhere out on the net. it wasn't a big issue. i generally find any real company doing any real business are working on pc's.
anyways i appreciate the response it confirms what i pretty well knew already.
thanks.
Orion
orion.buttigieg@Teamplate.com
www.Teamplate.com
|
|
|
|
|
ez2 wrote:
currently being ported to Linux via www.go-mono.com project
Before you say such things, you should know that this workforce decided a couple of weeks ago that making the System.Windows.Forms run with native code was just too hard, so they have decided to use a WIN32 emulator instead. Unfortunately, this emulator is known as something unreliable, bugged, uncomplete, ...
Open your eyes, and read : "System.Windows.Forms is currently being implemented using the Win32 API, we will be using WineLib on Unix systems to emulate the Win32 API. Although the original plans were to use Gtk on X and Cocoa on MacOS X, it would be very hard to emulate the event model in which some Winforms applications depend, and it would be very hard to implement the Wndproc method. "
This is an excerpt from go-mono[^].
She's so dirty, she threw a boomerang and it wouldn't even come back.
|
|
|
|
|
__Stephane Rodriguez__ wrote:
Before you say such things, you should know that this workforce decided a couple of weeks ago that making the System.Windows.Forms run with native code was just too hard, so they have decided to use a WIN32 emulator instead. Unfortunately, this emulator is known as something unreliable, bugged, uncomplete, ...
Open your eyes, and read : "System.Windows.Forms is currently being implemented using the Win32 API, we will be using WineLib on Unix systems to emulate the Win32 API. Although the original plans were to use Gtk on X and Cocoa on MacOS X, it would be very hard to emulate the event model in which some Winforms applications depend, and it would be very hard to implement the Wndproc method. "
What does that have to do with anything?
IMHO the popularity of Interop is far more of an obstacle to easy crossplatform ports than which library Mono is using to implement winforms.
|
|
|
|
|
Anonymous wrote:
IMHO the popularity of Interop is far more of an obstacle to easy crossplatform ports than which library Mono is using to implement winforms.
How do you show winforms then on Unix ? Surely the BSTR to String interop marshalling helps you a lot.  
How low can you go ?
(MS retrofuck)
|
|
|
|
|
Hello, when I create a Installer-Project for my .net
application, installer found a depend on "MFC70d.dll" and
include the dll. Ok, but when I try to install the
application on Win98/2000 installer throw an
exception "Unable to register mfc70d.dll". How can I
solve the problem?
|
|
|
|
|
Hello,
I created a COM object in ATL, that copy the screen and
retrurn it, by: HBITMAP struct.
When I add a reference, the: .NET, convert this type to:
IntPtr.
OK, I call to the function, get the: IntPtr. And use:
Bitmap bmp= Image.FromHbitmap(myIntPtrObj);
But than I get this exception:
System.Runtime.InteropServices.ExternalException
with this describe:
A generic error occurred in GDI+.
Please help me, how to solve this exception...
Thank's alot,
Itay.
|
|
|
|
|
If I programmatiacally want to determine whether .NET framework is installed on a computer and if so what version of .NET, how do I do this?
The project can not use .NET naturally since it also has to run on computers where .NET has not yet been installed. I've looked in the registry and found that I can use "RegOpenKeyEx()" on the registry key "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\policy\v1.0", but there must be a better way, since this call will fail if the user is running v1.1 . So how can I decide if and what version of .NET is installed on a computer?
Regards
/EnkelIk
|
|
|
|
|
If you app is being accessed or downloaded from the web, you can check the user agent of the request object. .Net adds the clr and version number to the user agent. Check out http://www.asp.net/webmatrix/download.aspx?tabindex=4 download section which uses the user agent to detect whether or not .net is installed. It's quick and simple. Hope this helps.
|
|
|
|
|
On the client-side, check out whether mscoree.dll exists (it's in <winsysdir>). That's the first thing a .NET app loads (to host the CLR).
Regarding the .NET version, you can lookup the registry : HKLM\Software\Microsoft\NET Framework Setup\Product\xxx with values defined as for instance :
Package="Full"
ProductLanguage="1033"
Version="v1.0.3705"
Version is like this
1 : major
0 : minor
3705 : build
She's so dirty, she threw a boomerang and it wouldn't even come back.
|
|
|
|
|
You could also check the for the existence of the path:
%windir%\Microsoft.NET\Framework\v1.0.3705
Ragards
Chris
|
|
|
|
|
Hi, i want to develop an application that use scriptable configuration file, like Macromedia Dreamweaver MX.
In Dreamweaver MX you can modify every dialog boxes just in modify a HTML/Javascript source. A windows dialog box is an HTML form, and you can't see the difference.
I just want to know what is this technology ? Is it .NET who give this capacity to do that ? A library ? or is Macromedia who invent that ?
Thank you for your answer.
gerti@hotmail.com
|
|
|
|
|
How do I create an off screen graphics object?
Basically, I want to draw some stuff to an off screen bitmap and them blt the lot to the main window graphics object.
This is NOT for double buffering. I need to be able to compose a small scene using transparency and then blt the translarent bitmap over the main screen which also has been drawn onto.
Any ideas gratefully accepted!
Pete
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
