Solved

VB COM compiling Issue

Posted on 2000-05-11
11
249 Views
Last Modified: 2013-11-25
Why in earth do you have to compile a VB dll twice? And why the first compile is always no compatibility?
0
Comment
Question by:gnagabandi
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
  • 2
  • +2
11 Comments
 
LVL 2

Expert Comment

by:Crin
ID: 2802362
Sorry, could you describe your problem in some more words?

As I understood, you mean that every compilation changes CLASSID for objects provided by your DLL, right?

Sincerely yours,

Crin
0
 

Author Comment

by:gnagabandi
ID: 2802379
Hi Crin,

You are right. But my question is Why we need to first compile with no compatability. What is the logic behind that?

Thanks,
Gang.
0
 
LVL 2

Expert Comment

by:Crin
ID: 2802477
I created a number of ActiveX dlls and EXEs and always used 'Project compatibility' option... Never had problems VB restrict me to select this option, do you have?

I'm sorry, english is not my native language... please describe your situation and why you compile your dll twice?

Sincerely yours,

Crin

0
Online Training Solution

Drastically shorten your training time with WalkMe's advanced online training solution that Guides your trainees to action. Forget about retraining and skyrocket knowledge retention rates.

 
LVL 15

Expert Comment

by:ameba
ID: 2802552
You don't have to compile twice. Compile ones. After that, set compatibility OF YOUR PROJECT to whatever you want.

Related links:
http://www.vb2themax.com/Item.asp?PageID=TipBank&ID=290
http://www.comdeveloper.com/articles/binarycomp.asp
0
 
LVL 2

Expert Comment

by:corvanderlinden
ID: 2803461
You have to compile twice.

The first time you compile set 'No compatiblity', compile and copy your DLL to a directory like for instance CompDlls
Then set Project Compatibility or Binary Compatability and reference your first compiled DLL in CompDlls. Then compile and make sure your new DLL is NOT in CompDlls. Then compile again and again .......

This has to do with VB not cluttering up your registry with GUID's, UUID's etc. every time you compile
There is a good article on the subject in MSDN:
Building, Versioning, and Maintaining Visual Basic Components

0
 
LVL 3

Expert Comment

by:Gordonp
ID: 2803514
corvanderlinden,

You only need to compile your Dll once to use it.

Only if you want to recompile your dll at a later stage (ie after an update) do you need to make the copy and set the compatability.

Gordon

0
 
LVL 3

Expert Comment

by:Gordonp
ID: 2803545
And your first ever compile has to be with no compatability because there nothing for it to be compatable with.
0
 
LVL 2

Expert Comment

by:Crin
ID: 2803854
gnagabandi,

Seems Gordonp phrases describes your problem very well. The only thing if compiler prohibit you to set 'Compatibility' option while first compiling. In fact sentence "And your first ever compile has to be with no compatability because there nothing for it to be compatable with." is the answer, I suppose :))

Sincerely yours,

Crin

0
 
LVL 2

Accepted Solution

by:
corvanderlinden earned 100 total points
ID: 2804061
GordonP
You are correct, and so am I. Read my original message's second line

Further you are right that you only have to follow my procedure the second time you compile but I make it a habit to follow this procedure alos on the first compile because it is my experience that you on a second compile often forget to first copy the original DLL (or ActiveX.EXE) and forget the Compatibility settings

Cor

0
 

Author Comment

by:gnagabandi
ID: 2809332
corvanderlinden,

I always follow your method only. But my question is why can't we create Binary Compatable Dll first time itself (I mean without No compatable).
0
 
LVL 2

Expert Comment

by:corvanderlinden
ID: 2809585
Binary Compatability cannot be set the first time because you first have to have a DLL to be compatable with. Binary Comp. means that the compiler checks the interfaces of the new DLL against the interfaces of the 'old' DLL (the one you specify in the components tab of Project properties).
If the interfaces change compatiblity is broken and the compiler has to assign new GUID's etc.
In a way the first DLL you compile (with No Comp.) is a blueprint for every new compile of your DLL.
(it is hard to describe in a few words but I hope this clarifies it a little)
0

Featured Post

Get HTML5 Certified

Want to be a web developer? You'll need to know HTML. Prepare for HTML5 certification by enrolling in July's Course of the Month! It's free for Premium Members, Team Accounts, and Qualified Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

You can of course define an array to hold data that is of a particular type like an array of Strings to hold customer names or an array of Doubles to hold customer sales, but what do you do if you want to coordinate that data? This article describes…
Entering time in Microsoft Access can be difficult. An input mask often bothers users more than helping them and won't catch all typing errors. This article shows how to create a textbox for 24-hour time input with full validation politely catching …
This lesson covers basic error handling code in Microsoft Excel using VBA. This is the first lesson in a 3-part series that uses code to loop through an Excel spreadsheet in VBA and then fix errors, taking advantage of error handling code. This l…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
Suggested Courses
Course of the Month11 days, 18 hours left to enroll

623 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question