HowTo make a dll, which can be called by VBA

mav northwind

Hi! You'll have to create a COM object for this, VBA cannot access a function in a .NET assembly.

Regards, mav -- Black holes are the places where God divided by 0...

Nader Elshehabi

What Mav said is true. But as an addition, you can write your code as C# and make your C# dll, then register it as COM dll then use it from your VBA macro. I think this post[^] would be helpful.

Regards:rose:

Ariadne

Really? Is it complicate to register a dll as com?

Ariadne

Nader Elshehabi

Well, not really. You can follow the link to the post I gave you in the previous reply. Here is the link again[^].

Regards:rose:

Ariadne

Thanks. If I use tlbexp I get only my class exposed, but not my methods. Any ideas? (I suppose, the methods have to have a certain format.) Nevertheless I do not belive, that a COM-object is the only way to get a connection to VBA. With a COM-object you do not need a Declare Function statement. But with a Declare Function one can access all routines eg. in the kernel.dll. (And that are not COM's in kernel.dll).

Ariadne

Nader Elshehabi

If you got your class exposed, how come not the methods in it?? Aren't they public? If there is some sort of a VBA .Net language then this would be a solution to your problem, bur otherwise there is no other direct conection between umanaged-to-managed code that I know of.

Regards:rose:

Ariadne

public class PW { public static string Convert5Bit(byte[] abytID) { //do somthing here ... return sConv; } } This is the declaration. But only PW as class is exposed. -- modified at 5:19 Thursday 26th October, 2006

Ariadne

Nader Elshehabi

First: Post your question to my answers, not to your question. I only saw your question by chance. Second: Try to reference to your new COM object in a C++ or C# project and see what is/isn't exposed Third: If none other works -I'm not that expert in VBA so if applicable- Make your method non-static, and call it form an instance of the class rather than the calss itself. Ps. BTW, what way did you know by it's not exposed?

Regards:rose:

SSLaks

VBA does not support static functions. Also, you are confusing Declare with COM. To get at an exposed COM object in VBA, ad a reference to it, then instansiate the class. Declare Function has nothing to do with COM - it uses access points, which cannot be created from C#. To create an access point, use an MFC dll. Schabse S. Laks

Ariadne

thanks for 1st. 2nd I look into the code with notepad and try in VBA the Object-Browser. both show only PW and not Convert5Bit() 3rd it tried that, but no success. thanks for your ansers! :rose:

Ariadne

ednrgc

you should check : ServicedComponent

Nader Elshehabi

Ariadne wrote:

Object-Browser. both show only PW and not Convert5Bit()

Well, in that object browser the method should be under the class name, shouldn't it? I mean you access the method by the class name? Also what file did you look into using the notepad?

Ariadne wrote:

3rd it tried that, but no success.

Define "no success"? You can't instantiate the object from the exposed class? Or the instance can't access the member function?

Regards:rose:

Ariadne

Nader Elshehabi wrote:

Also what file did you look into using the notepad?

I opened the tlb-File with notepad: There was no Convert5Bit.

Nader Elshehabi wrote:

object browser the method should be under the class name

Under the class name is no method. If I instantiate the class I get an runtime error: 429 ActiveX component can't create object. But VBA knows the class PW.

Ariadne

Nader Elshehabi

Well, I haven't tested the issue thoroughly. I did some googling and found this post on MSDN forum Post link[^] and here are two more articles in MSDN about the issue: Article 1[^] Article 2[^] Also I did what I told you. I made a tlb from the .Net dll, and it actually references to the class and the methods inside the class!! About the instantiation errer; Did you make your constructor public? I hope this directs you somewhere. Good luck! And I'm waiting for your feedback.

Regards:rose:

Ariadne

Thanks for your articles. I read a lot of stuff too.:omg: But it seams there is something basic wrong. here the story, what I try: 1. I build a classlibrary-project in VS8 C#. 2. I insert one TestDLL class: using System; using System.Collections.Generic; using System.Text; public class TestDLL { public string StringChange(string str) { return str +" from C#"; } } 3. I build the project with a TestDLL.dll as result 4. I run tlbexp TestDLL.dll /win 32 /out:TestDLL.tlb 5. An inspection of TestDLL.tlb with notepad.exe shows no StringChange string. 6. I run regasm TestDLL.dll It returns a waring: RA00000 : there are no types registered (retranslation from german) 7. I tested the same on a virgin VS8 Enviroment on my home notebook with the same result. 8. I have no idea....:(

Ariadne

Ariadne

That's it: in assemblyinfo.cs there is a switch: [assembly: ComVisible(true)] but it was false Now all works fine...:laugh: Thank you for your support Nader

Ariadne