Exposing a .Net assembly to both VB6 and .Net (1 more time)

2 Jun 2006 8:42 PM

Terry

I am finally able to call my .Net object from a VB6 project (see posting
'Calling VB.Net classes from VB6', thanks to the reference Tony gave me to:
article:http://msdn.microsoft.com/msdnmag/issues/06/05/WrapItUp/default.aspx

The next step was to see if I could still use the assembly in a .Net
application. I added another project to the original solution was was able
to create a reference to it through the projects tab, no problems so far.

I compiled the project with a strong signature and used the gacutil to place
it in the GAC. I verified with Windows explorer that it was there, and again
no problems.

I then created a new .Net project and tried to add a reference to it (from
the .Net tab) and it was not there! grrrr It was on the Com tab, so I tried
to ad the reference to it and got the following error message:

"A reference to 'Test Class' could not be added.

The ActiveX type library C:...\TestClass.tlb' was exported from a .Net
assembly and can not be added as a reference.

Add a reference to the .Net assembly instead."

BUT THE ASSEMBLY IS NOT LISTED ON THE .NET TAB!!!!

Ok, what to do now? Shouldn't I be able to share this assembly with several
..Net projects w/o including a local copy of it into each one?

--
Terry

4 Jun 2006 9:22 PM

rmacias

Terry,

The reason you can not see your DLL in the ".NET" tab is becasue the tab
does not reference the Global Assembly Cache. The files that you see in
there are copies of what is in the Global Assembly Cache located in other
locations. Look at the "Path" column of the ".NET" tab and you will see that
the assemblies in that list are not located in "C:\Windows\Assembly", but in
other places "C:\Windows\Microsoft .NET\Framework\".

The Global Assembly Cache is not a development feature, but a deployment
feature. When an assembly looks for a referenced DLL, it searches for it in
the following order:

1. Checks the assembly name to see if it is already bound. If so, then use
that one.
2. Checks the Global Assembly Cache.
3. Searches the app.config, machine.config, etc. for the location of the
referenced DLL.
4. Checks the application directory.

So what you should probably do is in your new Solution, you can either add
the Project or reference the *.DLL directly by browsing for it. Then, when
you deploy your new solution, if you place your .NET dll in the GAC, you new
solution will find it, as long as it was build with the same version number.

Hope this helps.

Show quoteHide quote

"Terry" wrote:

> I am finally able to call my .Net object from a VB6 project (see posting
> 'Calling VB.Net classes from VB6', thanks to the reference Tony gave me to:
> article:http://msdn.microsoft.com/msdnmag/issues/06/05/WrapItUp/default.aspx
>
> The next step was to see if I could still use the assembly in a .Net
> application. I added another project to the original solution was was able
> to create a reference to it through the projects tab, no problems so far.
>
> I compiled the project with a strong signature and used the gacutil to place
> it in the GAC. I verified with Windows explorer that it was there, and again
> no problems.
>
> I then created a new .Net project and tried to add a reference to it (from
> the .Net tab) and it was not there! grrrr It was on the Com tab, so I tried
> to ad the reference to it and got the following error message:
>
> "A reference to 'Test Class' could not be added.
>
> The ActiveX type library C:...\TestClass.tlb' was exported from a .Net
> assembly and can not be added as a reference.
>
> Add a reference to the .Net assembly instead."
>
> BUT THE ASSEMBLY IS NOT LISTED ON THE .NET TAB!!!!
>
> Ok, what to do now? Shouldn't I be able to share this assembly with several
> .Net projects w/o including a local copy of it into each one?
> --
> Terry

5 Jun 2006 6:53 AM

Walter Wang [MSFT]

Thank you rmacias again for your input.

Hi Terry,

As I described in the other thread that you've posted, the exposed COM
component from .NET using ComClassAttribute is not a true COM component.
When you want to use it from another .NET assembly, simply reference to it
as normal .NET assembly.

I totally agree with rmacias about the Visual Studio IDE reference tab and
the Global Assembly Cache. You can refer to MSDN for more info:

#Add Reference Dialog Box
http://msdn2.microsoft.com/en-us/library/ftcwa60a.aspx

Have a nice day!

Regards,
Walter Wang
Microsoft Online Community Support

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