Visual Basic

GuyThiebaut8-Oct-07 8:31

8-Oct-07 8:31

I agree with Dave.

It is well worth reading up on OOP to get at least an idea of how classes etc work.
It sounds like you are using a more procedural view point where macros, functions, constants etc are stored in a single place.

I mention this because coming from procedural languages myself I have had to shift my viewpoint - which can feel like parking an oil tanker in a space barely the size of a small car.

What I would suggest as a starter is to look at the wiki article on polymorphism - in fact here is a link Click Me.

Guy

You always pass failure on the way to success.

barney_19728-Oct-07 21:52

8-Oct-07 21:52

Thanks for the reponse.
I had already created the class but in light of your reponses i think i'll dispose of it and follow a better practice after reading up a little.

Cheers

barney_19728-Oct-07 22:03

8-Oct-07 22:03

I do have a reasonable knowledge of OOP concepts and can understand why to put the enums into their
respective classes, however i am a bit confused over the mention of polymorphism. I have read the link on Wiki.

Can you elaborate further why i need to undertand polymorphism in this case for moving the enums into their own classes?

Thanks

GuyThiebaut8-Oct-07 22:26

8-Oct-07 22:26

Hi,
Polymorphism is a concept in OOP where the same methods, properties etc can exist accross different objects and in essence behave differently.

For instance two classes called Aircraft and F1Car may have a method called Increase Throttle. The method for aircraft would increase the flow of air over the wings and cause lift whereas on the F1Car increasing the throttle would in effect cause the opposite to lift.

So you can have a method called Increase Throttle that exists across multiple objects and which has a different behaviour.

When it comes to programming you could even inherit the Aircraft methods, if you really wanted to, for the F1Car and override Increase Throttle to make it decrease lift.

The beauty of this is that, for instance with enums, you can declare the same methods or properties across multiple classes and they will behave accordingly - so no need to declare them once only and if you need a similar method for another class create something with a slightly different name (which is what you have do do in the area of procedural programming).

I hope this explains why understanding polymorphism helps.

Regards

Guy

You always pass failure on the way to success.

barney_19728-Oct-07 23:24

8-Oct-07 23:24

I understand Polymorphism better than before because of your explanation, thanks.

I am still confused how this applies to my Enums though.
Do you have an exact example of how this would apply using enums?

Thanks

Ps:-
To be honest what i was trying to do in the first place was probably bad practise, trying to put enums all in one place. I think as mentioned by someone ealrier they should be contained in each class.

GuyThiebaut8-Oct-07 23:37

8-Oct-07 23:37

Lets say you have an enum called SpeedWarning that applies to Aircraft and F1:

The Aircraft enums may be as follows

SpeedWarning:
TooSlowStall = 120
TooFastManeuver = 350

Whereas the F1 car may have

SpeedWarning:
TooFastDryCorner = 150
TooFastWetCorner = 80

So both Aircraft and F1 car have SpeedWarning as an Enum however they both have different contents and values.

So in this case you basically want to represent different applications of the enum SpeedWarning depending on the class they are associated with(Aircraft or F1).
If SpeedWarning was defined as an enum in one place you would lose the polymorphism properties of OOP as you would have to create something akin to SpeedWarningAircraft and SpeedWarningF1 enums.

Regards

Guy

You always pass failure on the way to success.

barney_19729-Oct-07 0:12

9-Oct-07 0:12

Guy,

Thanks alot - just needed a good example - could'nt see the Forest because the trees were in the way!! Big Grin | :-D

Thanks

GuyThiebaut9-Oct-07 0:30

9-Oct-07 0:30

No probs,

I'm glad it helps Smile | :)

.

Regards

Guy

You always pass failure on the way to success.

finger prints

shri508-Oct-07 5:25

shri50

8-Oct-07 5:25

hi i am making a project based on attendance report i want get the fingerprint in the textbox and store it in the database in another format

Re: finger prints

Dave Kreskowiak8-Oct-07 6:44

hi i want to make my software as trial version

8-Oct-07 6:44

What do you mean by "fingerprint"?? Is it the user's actualy fingerprint or some employee id number?? And how does this "fingerprint" relate to a TextBox? The name of that control should tell you something about how it works.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Re: finger prints

Christian Graus8-Oct-07 13:43

Christian Graus

8-Oct-07 13:43

Yet another person plans their project without any research...

If you have a fingerprint reader, it may have an SDK you can use. If you don't, you don't have any way of getting a fingerprint, right ?

A fingerprint will obviously be a bitmap. I suspect that a fingerprint reader will store other data about a fingerprint, for the purpose of comparison.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

shri508-Oct-07 5:23

shri50

8-Oct-07 5:23

hi i am doing a project on personal manager i want to make the project as trial version(not work more than 3or4 days)

advance thanks help me please!!!

Re: hi i want to make my software as trial version

ESTAN8-Oct-07 5:45

ESTAN

8-Oct-07 5:45

There are commercial tools available for this kind of tasks. But you can consider making something quick and dirty for yourself.

Store the date of first run somewhere (eg registry), best in an encrypted way. And every time open or access your application (event activated) you check the date and evaluate.

Developing and distributing licenced software

steve_rm8-Oct-07 4:39

steve_rm

8-Oct-07 4:39

Hello,

VS 2005.

I am creating some software and don't want the software to be installed on any other computers.

I can give it to the customer, but how can I avoid the customer from installing it on other computers.

I think I need to create some license so that the setup I give them will not be able to install if it has already been installed on another computer.

Which is the best practice when it comes to distributing software and to avoid the customer from installing on many computers?

Many thanks for any advice,

Steve

Dave Kreskowiak8-Oct-07 5:01

8-Oct-07 5:01

steve_rm wrote:
I can give it to the customer, but how can I avoid the customer from installing it on other computers.

Simple. You can't. It's impossible for you to stop the installation on another machine.

steve_rm wrote:
I think I need to create some license so that the setup I give them will not be able to install if it has already been installed on another computer.

Now, how is the other computer going to know that?

steve_rm wrote:
Which is the best practice when it comes to distributing software and to avoid the customer from installing on many computers?

There isn't one.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Christian Graus8-Oct-07 13:51

Christian Graus

8-Oct-07 13:51

I hate to disagree here, but it can be done, Windows does it now. It just involves a central server that tracks which keys have been used, and on what machines. 'Just' is an understatement, it's a fair bit of work and an inconvenience to end users.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Dave Kreskowiak8-Oct-07 13:57

8-Oct-07 13:57

Christian Graus wrote:
I hate to disagree here, but it can be done, Windows does it now.

Oh I know that. In order for this to work, the machines all have to have access acrossed a network to some central license server.

But in the case of disconnected PC's, it's impossible to do.

Christian Graus wrote:
'Just' is an understatement, it's a fair bit of work and an inconvenience to end users.

Not to mention beyond the abilities of way too many "developers"! Big Grin | :-D

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Vimalsoft(Pty) Ltd8-Oct-07 5:21

Vimalsoft(Pty) Ltd

8-Oct-07 5:21

hi steve_rm

i think the solution for is to get a third party software that will do that for you, http://application-licensing.qarchive.org/[^].Next thing you should do is to learn Encription. how it works. your question is vast. try to google about encryption or get some e-books on that.

hope it helps

Vuyiswa Maseko,

Sorrow is Better than Laughter, it may Sudden your Face, but It sharpens your Understanding

VB.NET/SQL7/2000/2005
http://vuyiswamb.007ihost.com
http://Ecadre.007ihost.com
vuyiswam@tshwane.gov.za

GuyThiebaut8-Oct-07 8:42

8-Oct-07 8:42

What I have done is to create a EULA by copying another EULA that is close enough to what I want and then modify it.

In terms of the law, from what I understand, if your EULA is written in good logical English that should do.
It does not need to be written in legalese in order to sue the hell out of whoever re-distributes your software - ooh I'll just calm down for a minute.

I also create trial versions that stamp the registry with an encrypted date so that the software stops working when the date passes.
To activate the software the user needs to buy the activation key from me - which is basically whatever keys my pet gerbils walk over on my keyboard (my best randomization routine yet!).

My take on it is that if the user is brainy enough to crack the registry location and break the code - they can have the software.

Also another good idea - in the trial version have certain aspects disabled which can only be enabled with the registration key - this will get your users hungry for more.

If they decide to sell the registration key themselves then I guess you could sue them.

You always pass failure on the way to success.

ID card mag stripe encoding

Christian Graus8-Oct-07 13:50

Christian Graus

8-Oct-07 13:50

The way to do this, is to create a machine level key which is used to build a response key. Like windows does. Then, you store an online database of those keys that have been used, so they cannot be used again.

So, the key is unique to a PC, and it ties in with a akey they have to enter. Then your central method works out what the key was, marks it as used, and returns the correct response.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Monte at Oaklawn8-Oct-07 4:36

Monte at Oaklawn

8-Oct-07 4:36

I need to be able to print ID cards with magnetic stripes from a VB.NET application. Encoding the mag stripe is a simple matter of putting special code characters in the text to print. I can print text to the card printer from Notepad, ConText or any other text editor, and the printer knows to encode the stripe. This even works printing from a report in Access, but not from a Crystal report, and not from the .NET PrintDocument object. All these do is print the information to be encoded on the front of the card.

So anyway, I need to print simple text from a .NET app without using .NET printing objects or Crystal.

Re: ID card mag stripe encoding

Dave Kreskowiak8-Oct-07 4:59

Re: ID card mag stripe encoding

8-Oct-07 4:59

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=320741&SiteID=1[^]

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Monte at Oaklawn10-Oct-07 9:30

Monte at Oaklawn

10-Oct-07 9:30

Thanks, but since the printer is not a POS device, this is not going to work.

If there was a print utility that could be called from VB.NET, that would suffice, if there is no way to send text directly to a printer driver in VB.NET.

Re: ID card mag stripe encoding

Dave Kreskowiak10-Oct-07 14:54