C# DLL Calling From Excel 32 Bit Vs 64 Bit

Hi,

I have a very simple addition DLL.

In the VBE > Tools > References I add the .tbl File.

Below is the code that I use

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The Code runs fine on a 32 Bit Excel version, but errors out on 64 Bit.

1 observation though, even though the Code errors out on the 64 Bit, the Intellisense (DLLs Methods) are available at design time.



Can anyone help me with this??

Cheers!

Deep

Originally Posted by Marc L

Hi !

A must read : Declaring API functions in 64 bit Office …

Hi,

Thank you for the reply. I have already been though the documentation before posting. Unfortunately still haven't gotten it to work

I have been through a few links online, but none seem to get me code working.

As far as I am aware you will need to compile a 64bit version of your dll.

Originally Posted by xlnitwit

As far as I am aware you will need to compile a 64bit version of your dll.

Hi.

Thank you for the reply.

Can you share me some sort of documentation which shows what exactly needs to be done. I will need to share it with the guy who has made the DLL?

Cheers

I would think he should know how to do that. If using visual studio you just select the target platform when building the dll.

Hi,

The communication from the guy who made the dll says that the Target Platform is set to "Any CPU" which should work on both.

However, to try it out, we built the dll again with Target Platform set to x64. It still does not work.

Ref Link we used - https://msdn.microsoft.com/en-us/library/ms185328.aspx

This is not really a VBA issue, and without the code for the dll I couldn't really comment as to why it doesn't work on 64 bit.

Here is the DLL Code as required -

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;

namespace Calculation
{



[Serializable(), ClassInterface(ClassInterfaceType.AutoDual), ComVisible(true)]
public class Main
{
public calculate Sum_num()
{
return new calculate();
}
}

[Serializable(), ClassInterface(ClassInterfaceType.AutoDual), ComVisible(true)]
public class calculate
{
public double Add(double a , double b)
{
return a + b;
}
}



}

It works fine here for 64 bit. Are you sure you set the build options properly for Release, not Debug?

Yes, we have set it for Release and not debug.

Is there a possibility you can share the dll made by you which is working at your end? Since we know it works on 64 Bit on your PC. If it does not work on mine, we can be certain there is some other issue.

Cheers!

Here it is.

Hi,

Thank you for the reply. The dll shared by you isnt working at my end. I am getting the same error I was getting previously.

I tried it on another PC that has 64 Bit Excel, but it isn't working there as well.

Do you think there can be an issue with 32Bit Windows Vs 64 Bit Windows??

Cheers!

Did you register the dll successfully? Did Calculation appear in the reference list, or did you have to browse to the dll?

I don’t see how the bitness of windows could be relevant since we both must be running 64 bit.

Yes.. From the VBE > Tools > Reference, I set a reference to the tlb file.

I was even able to access the intellisense from the dll.

But after running the code, I get an error 429 - ActiveX component can't create object

Just to confirm- you could see Calculation already in the list of available references, and you did not have to browse to the actual file?

Which version of Windows are you using?

I was able to see Calculation already in the list of available references, but I put your DLL & TLB in a different folder to avoid any confusion. Then I browsed to that folder again and and set the reference.

I am using Windows 10

If you already had your Calculation dll installed, I suggest you uninstall it, then install the new dll and select it directly from the references dialog, not by browsing.

Originally Posted by xlnitwit

If you already had your Calculation dll installed, I suggest you uninstall it, then install the new dll and select it directly from the references dialog, not by browsing.

Hi,

I am not able to understand. How do you uninstall the dll?

All I did was place my DLL & TLB in 1 folder, and selected the TLB from that path in references.

You unregister it using whatever you used to register it in the first place (regasm or regsvr presumably).

Originally Posted by xlnitwit

You unregister it using whatever you used to register it in the first place (regasm or regsvr presumably).

OMG, I haven't done any of that.. I did not know you need to register it. Isn't just adding the reference enough?

On my 32-Bit Excel, I haven't done any of the registration part and it still works..

Was the dll built on that machine? Or did you run a setup program? I'm not sure how it would appear in the reference list if it had not been registered somehow.

The DLL was built on a colleagues PC, and was sent to me.

It would appear in the reference list by clicking the browse button and browsing to that location.

I have done using this method numerous times previously. I was absolutely not aware that the dll needs to be registered before.

I asked previously if you could see it in the list without browsing to the file.

As far as I know, .Net assemblies should be registered to be used with COM. After downloading the dll I posted earlier to a machine with 32bit Office but 64bit Windows, I confess I can't register it correctly (that may be a permissions issue at work). I can however set a reference to the tlb and see the Intellisense as you can but also get a 429 error when trying to run the code, which is not unexpected for a 64bit dll I think. Trying to set a reference to the dll rather than the tlb fails.

Alright.. Seems the problem is more complicated than I thought.

Anyways, I will keep you updated if I find a solution.

Thank you very much for your time.

Rep Added for all the help.

Cheers!
Deep

By the way, do you get this error on a 32 Bit Excel?

No, I just get a 429 error.

I have just built a 32 bit version on my work computer and it does seem to work without registering it. I will have to check the 64 bit one on another computer when I have access to one.

Hi AB33,

Thank you for the reply..

I have both versions 32 & 64 Bit..

My Code works flawlessly on 32 Bit, but the same code gives me the 429 Error on 64 Bit.

Its absolutely frustrating..

Originally Posted by xlnitwit

No, I just get a 429 error.

I have just built a 32 bit version on my work computer and it does seem to work without registering it. I will have to check the 64 bit one on another computer when I have access to one.

No Problem,

Thank you for the help so far