Re: Data Storage? - C / C++ / MFC Discussion Boards

Balaji Krishna8-Jul-05 19:39

8-Jul-05 19:39

How to monitor the folder in the MFC.Suppose the new file is come to that folder ,it indicate the file name.Please Urgent .Help me

Sunsen

Re: Monitor The Folder

ThatsAlok8-Jul-05 20:07

ThatsAlok

8-Jul-05 20:07

sunsen wrote:
How to monitor the folder in the MFC

This Api Will Help :- ReadDirectoryChangesW

Here is an Article, that might help you :-

http://www.codeproject.com/file/directorychangewatcher.asp[^]

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta

Re: Monitor The Folder

David Crow9-Jul-05 10:23

David Crow

9-Jul-05 10:23

There's also FindFirstChangeNotification().

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Data Storage?

S Douglas8-Jul-05 19:34

S Douglas

8-Jul-05 19:34

Okay, I don’t get it. Perhaps someone can help me out a little. I set up a client / server over Winsock no problems. But once a client receives the data from the server what’s the best way of storing that information for later use?

Here is an example of the type of data I'm receiving at the client end

WorkOrder | Date | SiteNumber | SiteContact | SitePhone | Device | Summary | Comments
00001 | 07/09/05 | 0001 | Joe | 111-111-1111 | 1 | Test | Test
00002 | 07/10/05 | 0001 | Jane | 111-111-1111 | 0 | Test2 | Test2
Etc

The number of rows is variable (depending on how many service calls exist). I started using a simple pointer to a struct. But that “feels” messy, is there a better way? I know there are several different types of single dimension arrays in C++, but I have yet to find a multi-dimensional array.

Any pointers anyone? Hope My post was clear. Thank you for you time and consideration.

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Re: Data Storage?

ThatsAlok8-Jul-05 20:54

ThatsAlok

8-Jul-05 20:54

sfdougl wrote:
I started using a simple pointer to a struct. But that “feels” messy, is there a better way?

Why are you going after OLD C method such like creating your own link list and other collection, when there are dozens of Collection classes available in market such as STL or MFC Collection classes, that are much more optimized and fast.

You just have to implement you structure in that collection classes!.

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV

Re: Data Storage?

S Douglas8-Jul-05 21:30

S Douglas

8-Jul-05 21:30

ThatsAlok wrote:
Why are you going after OLD C method such like creating your own link list and other collection, when there are dozens of Collection classes available in market such as STL or MFC Collection classes, that are much more optimized and fast.

You just have to implement you structure in that collection classes!.

I knew I was doing something wrong. That’s why I stopped at a certain point and said wait a minute, there has to be a better way. Can you point me to something explaining structures in collection classes?

Thank you

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Re: Data Storage?

S. Senthil Kumar8-Jul-05 21:35

S. Senthil Kumar

8-Jul-05 21:35

Look for the STL (Standard Template Library) collection classes. The vector class behaves like a dynamically expandable array, if you want linked list like behaviour, there is the list class and so on. Using those classes is very simple.

vector <YourStruct> v;

You can then use methods on v to add and remove elements from the collection.

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: Data Storage?

S Douglas8-Jul-05 22:09

S Douglas

8-Jul-05 22:09

Sorry if I'm being a little dense here but still not clear. I understand that Arrays, Vectors, Linked Lists are all good for housing data. The thing I need is multiple columns.

If I may be so bold to speculate but to do what I need would I create a class to wrap together the collections and access the data via member functions? Or is there a pre written object?

Your example was hidden.
So could I do something as simple as?

(Sorry pseudo code here, I'm not anywhere near my developing environment)

<br />
struct WORKORDER <br />
{<br />
int WorkOrder; <br />
CString Date;<br />
Cstring SiteNumber;<br />
Cstring SiteContact;<br />
...<br />
} <br />
<br />
vector <WORKORDER> v;<br />

Referencing the data members like so
Int iWo = V[0].WorkOrder

I'm not opposed to doing a little work. I just don’t want to do work that’s well incorrect. Thanks for the help.

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Re: Data Storage?

S. Senthil Kumar8-Jul-05 22:16

S. Senthil Kumar

8-Jul-05 22:16

Yes, you're on the right track. A vector can be used as a collection of *anything*, even a collection of vectors etc. So yes, you could store a collection of instances of your structure, so you'd get the multi column array functionality you wanted.

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: Data Storage?

S Douglas8-Jul-05 22:23

S Douglas

8-Jul-05 22:23

Ah okay, so its no where near as complicated as I was thinking. Blush | :O

Man, You and everyone else who helped are life savers.

Smile | :)

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Re: Data Storage?

Cedric Moonen8-Jul-05 22:19

Cedric Moonen

8-Jul-05 22:19

Yes, that's it. You create a structure that contains all the fields for one 'worker' (so contains all the data for one 'row'). And then you can use the vector:

std::vector<WORKORED> YourVector;<br />
WORKORDER Data;<br />
// Fill Data<br />
//<br />
//<br />
YourVector.push_back(Data);<br />
// Fill other structures<br />
//<br />
//

Then, to retrieve one data of the vector:

WORKORDER Data = YourVector[0];

Then you can work with the structure.

Re: Data Storage?

S Douglas8-Jul-05 22:27

S Douglas

8-Jul-05 22:27

cedric moonen wrote:
Yes, that's it. You create a structure that contains all the fields for one 'worker' (so contains all the data for one 'row'). And then you can use the vector:

std::vector<workored> YourVector;
WORKORDER Data;
// Fill Data
//
//
YourVector.push_back(Data);
// Fill other structures
//
//

Then, to retrieve one data of the vector:

WORKORDER Data = YourVector[0];

Then you can work with the structure.

Perfect! Just what I needed to make the necessary connections in the old Gray matter.

Thank You, Cedric. Smile | :)

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Re: Data Storage?

ThatsAlok8-Jul-05 22:42

ThatsAlok

8-Jul-05 22:42

sfdougl wrote:
Can you point me to something explaining structures in collection classes?

Yeap, just check out this link :-
http://www.codeproject.com/vcpp/stl/[^]

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV

Re: Data Storage?

S Douglas8-Jul-05 22:49

S Douglas

8-Jul-05 22:49

Thanks for the reading material. Your help is appreciated.

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Re: Data Storage?

S Douglas9-Jul-05 20:38

S Douglas

9-Jul-05 20:38

ThatsAlok wrote:
sfdougl wrote:
Can you point me to something explaining structures in collection classes?

Yeap, just check out this link :-
http://www.codeproject.com/vcpp/stl/[^]

I found an article in the STL that explains Vectors quite well. Thought I would post it in case some else has this same problem.

A Presentation of the STL Vector Container - STL[^]

Thanks Everyone for you help.

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Re: Data Storage?

John R. Shaw8-Jul-05 22:03

John R. Shaw

8-Jul-05 22:03

Alright, I'll take a stab.

The most simplistic form of a record is that provided by an C-structure, it has the advantage of being a fixed size (speed of access). It also means that it may waste memory, because irregardless of the actual size required, you have to allocate enough memory to store (a fixed size for) each record..

You can create a class that reads a record on a per-field basis....

I am sorry, but I can't explane more at this time (it is almost 4AM and my brain just locked up).

INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen

Re: Data Storage?

S Douglas8-Jul-05 22:22

S Douglas

8-Jul-05 22:22

John R. Shaw wrote:
The most simplistic form of a record is that provided by an C-structure, it has the advantage of being a fixed size (speed of access). It also means that it may waste memory, because irregardless of the actual size required, you have to allocate enough memory to store (a fixed size for) each record..

Thanks John,

If I understand your post correctly that’s more or less what I did initially to solve the problem. A struct controlled by a class, but it just “felt” incorrect.

John R. Shaw wrote:
I am sorry, but I can't explane more at this time (it is almost 4AM and my brain just locked up).

Don’t worry, I have been toiling over this for a few days now. I'm in no real hurry, the boss is used to me laughing at his ridiculous deadlines.

Thanks for you input.

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Re: Data Storage?

Ravi Bhavnani9-Jul-05 7:00

Ravi Bhavnani

9-Jul-05 7:00

See my serialization[^] tutorial.

/ravi

My new year's resolution: 2048 x 1536
Home | Articles | Freeware | Music
ravib@ravib.com

Re: Data Storage?

S Douglas9-Jul-05 18:04

S Douglas

9-Jul-05 18:04

Okay, will do, Thanks Ravi

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strange error in vc

wrb3028-Jul-05 19:03

wrb302

8-Jul-05 19:03

create a new mfc sdi project, in onDraw fuction add the following:
pDC->SetDCPenColor(RGB(0,0,0));

when compile, this error happens:
error C2039: 'SetDCPenColor' : is not a member of 'CDC'

according to msdn, CDC has this member. when i input these, there is even a auto completion.

how could this happen?

Re: strange error in vc

Jack Puppy8-Jul-05 20:11

Jack Puppy

8-Jul-05 20:11

Requirements
Windows NT/2000/XP: Included in Windows 2000 and later.
Windows 95/98/Me: Unsupported.

1) Are you using Win 9x?

2) The code for SetDCPenColor is wrapped using

#if (_WIN32_WINNT >= 0x0500)

so you'd need to set the _WIN32_WINNT constant to at least 0x0500 (which should be the constant for Win2K) in the stdafx.h file in your project.

Pssst. You see that little light on your monitor? That's actually a government installed spy camera. Smile and wave to big brother!

Painted on the side of a dog trainer's van: SIT HAPPENS

Re: strange error in vc

wrb3029-Jul-05 21:06

wrb302

9-Jul-05 21:06

set 0x0500 works.

thanks.

Re: strange error in vc

John R. Shaw8-Jul-05 20:57

John R. Shaw

8-Jul-05 20:57

What version of the IDE are you using, because SetDCPenColor() does not exist.

CPen pen(PS_SOLID,1,0); // or pen(PS_SOLID,1,RGB(0,0,0));
CPen* pOldPen = pDC->SelectObject(&pen);
... draw something
// clean up!
pDC->SelectObject(pOldPen)

INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen

visual c++ custom controls.

rich1358-Jul-05 15:29

rich135

8-Jul-05 15:29

Ok- basic question:

Ive downloaded source files and the accompanying .ocx file for use in a basic visual c++ project. The .ocx file works.

Now- when i edit the source files a bit to add new functuality, how the heck do I recompile them using visual studio into a brand new .0cx file??? Im lost on this aspect.

rich

Re: visual c++ custom controls.

John R. Shaw8-Jul-05 16:30

John R. Shaw

8-Jul-05 16:30

The same way you would any other program or dll.

If it came with a VC project file then that should not have a problem.

If it did not and it is VC code, you could try:
1) Create a new ALT COM AppWizard project, with the same name as the current ocx.
2) Add your files to the project. This will involve replacing the app-wizard generated files with your files.
3) Goto the project settings, find output file name (under the link tab) and replace the .dll extension with the .ocx extension.
4) Compile.

Suggestions (before you try above):
1) Create a simple ocx project, to get used to the process.
2) Try the above with copies of the original files, before using your modified files.

P.S. Andrew W. Troelsen is the author of a book on creating ALT COM (ocx) controls.

INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen

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