HowTo make a dll, which can be called by VBA

[Ariadne]

Hi, are there any roules for a dll written in C#, which can be called by a VBA Macro? Private Declare Function foo Lib "foo.dll" (sfoo as string) as string How does the C# code for such dll look like?

Ariadne

[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