VB & Database, What is diff. class Class Module & Module

What is diff. class Class Module & Module

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Matthe #1 / 10	What is diff. class Class Module & Module What is diff. class Class Module & Module
Sun, 20 Jun 2004 22:32:38 GMT

Val Mazu #2 / 10	What is diff. class Class Module & Module Hi, Actually this is newsgroup which discusses ADO, not general VB questions. But in general Module is a container for procedures, functions and variables (not method and properties). You cannot create and use instance of module as an object. In Class Module all public procedures/functions and variables are methods and properties of that class and you can create multiple instances of that class using object valiables. For example dim MyVar as MyClass set MyVar=new MyClass MyVar.DoSomething 'Call DoSomething method set MyVar=nothing probably you need to post you question to another newsgroup to get more detail information Val Quote: >-----Original Message----- >What is diff. class Class Module & Module >.
Sun, 20 Jun 2004 22:48:35 GMT

Max Bolingbrok #3 / 10	What is diff. class Class Module & Module No problem :) Class modules are designed for code reuse, so that code does not have to be replicated. Its like having a user defined type which can perform functions without any extra programming. Once you have programmed them once you can create "instances" of them in your main code, which you then manipulate like an object. Another big advantage is that you can load them into arrays, which is dead handy when you want to have lots of identical objects. If you have ever used the FileSystemObject, that is a good example of a class module (made by Microsoft though) Creating a class module is simple - just add public subs/functions to it for subs/functions that you want the user to know about, and add private subs/functions for ones which are called from within your code. You can also add properties, like in user controls, which expose private variables to the main program. To use a class module, first dim a variable as the module: Dim Whatever As clsWhatever Then "set" the module: Set Whatever = New clsWhatever You can then manipulate the module: Whatever.WhateverSub Whatever.Whatever = 50 Var = Whatever.WhateverFunction To create arrays of them, just dim the module like a normal array: Dim Whatever() As clsWhatever or Dim Whatever(50) As clsWhatever And access it normally. Class modules are great because it means you can easily reuse code, in these little self contained units. As long as you supply some good documentation along with it, another programmer can use it far more easily than a normal module. Class modules can also have events like controls. Just declare the event in the General section of the class module: Event Whatever(What As String, Ever As Integer) And the raise it whenever it needs to happed: RaiseEvent Whatever("Hi", 50) To use a class module with events, declare it WithEvents: Dim WithEvents Whatever As clsWhatever And you will see its name in the left combo box on the code view. Class modules have another advantage - they can "Implement" an interface. An is a class module with only defentions of functions, which your class module then programs. This is very useful in a client / server environment, but its a bit tricky to explain. There are some good books around on COM and this subject. And thats all there is to it :) Whew. Hope this was helpful! Max Bolingbroke
Sun, 20 Jun 2004 23:21:03 GMT

Sandip Sing #4 / 10	What is diff. class Class Module & Module This site has answer to your question. Thanks http://www.vbwm.com/art_1997/ser_cls1.htm Quote: >-----Original Message----- >What is diff. class Class Module & Module >.
Mon, 21 Jun 2004 01:11:25 GMT

Joe #5 / 10	What is diff. class Class Module & Module Quote: > What is diff. class Class Module & Module Use a class module (or a Type) to hold things you might want more than one of. You can use class modules to keep you from ever forgetting to turn off the hourglass or close a file, even in case of an error: http://www.csdn.net/dev/Visual%20Basic/document/E-Tips/e-tips/e-tips1... http://groups.google.com/groups?selm=u2vbubhresc0b1%40corp.supernews.com Note that this technique, called "resource management" or "resource acquisition is initialization", can.NOT be done in what Microsoft seems to be calling "the next version of Visual Basic". Don't drink the koolaid. -- Joe Foster <mailto:jlfoster%40znet.com> Greed = God? <http://www.xenu.net/> WARNING: I cannot be held responsible for the above They're coming to because my cats have apparently learned to type. take me away, ha ha!
Mon, 21 Jun 2004 02:27:55 GMT

Yutin #6 / 10	What is diff. class Class Module & Module That was a very good description. As a newbie, I found it very useful and will now start using these wonderful class modules The Green Giant -- At first there was nothing. Then God said 'Let there be light!' Then there was still nothing. But you could see it. Quote: > No problem :) > Class modules are designed for code reuse, so that code does not have to be > replicated. Its like having a user defined type which can perform functions > without any extra programming. > Once you have programmed them once you can create "instances" of them in > your main code, which you then manipulate like an object. Another big > advantage is that you can load them into arrays, which is dead handy when > you want to have lots of identical objects. > If you have ever used the FileSystemObject, that is a good example of a > class module (made by Microsoft though) > Creating a class module is simple - just add public subs/functions to it for > subs/functions that you want the user to know about, and add private > subs/functions for ones which are called from within your code. You can also > add properties, like in user controls, which expose private variables to the > main program. > To use a class module, first dim a variable as the module: > Dim Whatever As clsWhatever > Then "set" the module: > Set Whatever = New clsWhatever > You can then manipulate the module: > Whatever.WhateverSub > Whatever.Whatever = 50 > Var = Whatever.WhateverFunction > To create arrays of them, just dim the module like a normal array: > Dim Whatever() As clsWhatever or > Dim Whatever(50) As clsWhatever > And access it normally. > Class modules are great because it means you can easily reuse code, in these > little self contained units. As long as you supply some good documentation > along with it, another programmer can use it far more easily than a normal > module. > Class modules can also have events like controls. Just declare the event in > the General section of the class module: > Event Whatever(What As String, Ever As Integer) > And the raise it whenever it needs to happed: > RaiseEvent Whatever("Hi", 50) > To use a class module with events, declare it WithEvents: > Dim WithEvents Whatever As clsWhatever > And you will see its name in the left combo box on the code view. > Class modules have another advantage - they can "Implement" an interface. An > is a class module with only defentions of functions, which your class module > then programs. This is very useful in a client / server environment, but its > a bit tricky to explain. There are some good books around on COM and this > subject. > And thats all there is to it :) Whew. > Hope this was helpful! > Max Bolingbroke
Mon, 21 Jun 2004 09:14:52 GMT

Calvin Crumrin #7 / 10	What is diff. class Class Module & Module Good luck. The biggest 'lie' in that excellent description is "Creating a class module is simple". That's right, except that it runs afoul of the eternal bugaboo of code reuse. It's never simple to write reusable code. What typically happens is something like this. You write a program for a specific purpose. In doing that you see an opportunity to create a reusable class so you do so. When you reuse the class in the next program however you find that the routines aren't sufficiently generic-what worked perfectly in the first program doesn't quite fit the second program. So you either 'break' the first program by modifying the routine or add a second, almost identical routine, for the second program. While the second approach works it's rarely better than just coding the routine into the program in the first place. Where writing class modules really works is when you have a bunch of programs in simultaneous development which reuse the code. Given enough programs you'll cover enough variables that the code you write in the class module will actually handle everything. Otherwise it's an iterative process that involves eternally 'fixing' the earlier programs to account for changes required by later ones. Quote: > That was a very good description. > As a newbie, I found it very useful and will now start using these wonderful > class modules > The Green Giant
Tue, 22 Jun 2004 03:43:19 GMT

Max Bolingbrok #8 / 10	What is diff. class Class Module & Module I find it simple :-), and only write generic class modules or very specific ones so as to keep it even simpler Max Bolingbroke Quote: > Good luck. > The biggest 'lie' in that excellent description is "Creating a class module is > simple". That's right, except that it runs afoul of the eternal bugaboo of code > reuse. It's never simple to write reusable code. > What typically happens is something like this. You write a program for a > specific purpose. In doing that you see an opportunity to create a reusable > class so you do so. > When you reuse the class in the next program however you find that the routines > aren't sufficiently generic-what worked perfectly in the first program doesn't > quite fit the second program. So you either 'break' the first program by > modifying the routine or add a second, almost identical routine, for the second > program. While the second approach works it's rarely better than just coding the > routine into the program in the first place. > Where writing class modules really works is when you have a bunch of programs in > simultaneous development which reuse the code. Given enough programs you'll > cover enough variables that the code you write in the class module will actually > handle everything. Otherwise it's an iterative process that involves eternally > 'fixing' the earlier programs to account for changes required by later ones. > > That was a very good description. > > As a newbie, I found it very useful and will now start using these wonderful > > class modules > > The Green Giant
Tue, 22 Jun 2004 04:14:07 GMT

Gilmou #9 / 10	What is diff. class Class Module & Module I reuse all the time...just remember what it takes to write generic code. I also like to remember the definition of a class...the data and the methods to manipulate the data. Remember that and your a happier man. The people I see having the most difficulty with classes are people who use them for repositories of functions...that would be a module. Designing and writing good classes, regardless of implementation language, was one of my favorite classes in college. I recommend a class like it to everyone! -- TNB (Tim Walsh - You might find me in the yellow pages!) Quote: > Good luck. > The biggest 'lie' in that excellent description is "Creating a class module is > simple". That's right, except that it runs afoul of the eternal bugaboo of code > reuse. It's never simple to write reusable code. > What typically happens is something like this. You write a program for a > specific purpose. In doing that you see an opportunity to create a reusable > class so you do so. > When you reuse the class in the next program however you find that the routines > aren't sufficiently generic-what worked perfectly in the first program doesn't > quite fit the second program. So you either 'break' the first program by > modifying the routine or add a second, almost identical routine, for the second > program. While the second approach works it's rarely better than just coding the > routine into the program in the first place. > Where writing class modules really works is when you have a bunch of programs in > simultaneous development which reuse the code. Given enough programs you'll > cover enough variables that the code you write in the class module will actually > handle everything. Otherwise it's an iterative process that involves eternally > 'fixing' the earlier programs to account for changes required by later ones. > > That was a very good description. > > As a newbie, I found it very useful and will now start using these wonderful > > class modules > > The Green Giant
Tue, 22 Jun 2004 04:32:20 GMT

Steve Walke #10 / 10	What is diff. class Class Module & Module Quote: >Good luck. >The biggest 'lie' in that excellent description is "Creating a class module is >simple". That's right, except that it runs afoul of the eternal bugaboo of code >reuse. It's never simple to write reusable code. It requires thought, I'll grant you, and reuse is achieved far too little, but it's far from impossible. Given how much VB developers reuse other people's code (ADO, MSXML, FileSystemObject, OLEDocumentProperties, a million third-party activeX controls, etc), we should be pretty aware of what it takes. Quote: >Where writing class modules really works is when you have a bunch of >programs in >simultaneous development which reuse the code. Given enough programs you'll >cover enough variables that the code you write in the class module will >actually >handle everything. This is true; in my current project we have a reusable XSL transform class which manages the caching of MSXML template objects in the ASP application which is reused in many places in a large app. On the other hand, it does a much more efficient job than the system in my previous project, so I shall soon be using it there, and I expect it to pop up in any future web apps that do xforms on the server. -- Steve Walker
Wed, 23 Jun 2004 06:14:39 GMT

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