Help on Class Design

seburnDavenport · October 27th, 2009, 01:47 AM

Hi! I am new to OOP and about half way through the book. I was just starting to grasp the concept of class design and I'm running into an issue. I don't know whats wrong. I'm referring to Chapter 9 - Part 3 - Writing your own classes. I wrote the clsDates class and on p 230 where I'm trying to instantiate a clsDates object named myDate and am getting the following error: The type or namespace name 'clsDates' could not be found (are you missing a using directive or an assembly reference?). I am comparing my code to yours and it identical! I am really trying hard to figure out what I'm doing wrong...Can you help??
Thanks for your time!

DrPurdum · October 29th, 2009, 07:57 AM

Without actually seeing your code, my best guess is that you do not have the class code included in the project. The code you see starting on page 225 must be included in your project's namespace. Otherwise, VS doesn't know where to look for the class. Make sure that code is in the proper template type (i.e., class). See page 209 and make sure you place the class code in a class template in your project. That should take care of it.

seburnDavenport · October 29th, 2009, 09:40 AM

Thanks for the response, I truly appreciate it. I will try this is hopefully it corrects the issue. So, I when I create the classDesign project I need to add a class file and add the clsDates code to that page? Is there anything else I need to do to make that clsDates class visible to VB? Also in the future when I want to instantiate a clasDates object from another program I am writing, do I also have to add a class file and include the code for clsDates or will VB know where how to access it if I just say clsDates myDate = new clsDates();?
Thanks again for your help, it is greatly appreciated. And I really love the book, it's definitely the best material out there.

DrPurdum · October 29th, 2009, 12:57 PM

Yes, you will need to include the class code in any project that uses it. Once VS sees the the source code file in the project, it has no problem finding references to it.

After you get a little experience, you can learn how to compile the class into a Dynamic Link Library (DLL) file and then just add a reference to it to your project, just like you for the standard Windows library references...but that's another topic.

DrPurdum · October 29th, 2009, 12:57 PM

Yes, you will need to include the class code in any project that uses it. Once VS sees the the source code file in the project, it has no problem finding references to it.

After you get a little experience, you can learn how to compile the class into a Dynamic Link Library (DLL) file and then just add a reference to it to your project, just like you for the standard Windows library references...but that's another topic.

seburnDavenport · October 29th, 2009, 04:51 PM

Well that certainly clears up alot. Thanks for your help, I'm glad I decided to post.