[AccessD] Access 2010 or later - storing and referencing code in libraries

[Jim Dettman]

John,

<< VB_Exposed=True VB_Creatable=True>>

 Did it work?   

Jim.

-----Original Message-----
From: AccessD On Behalf Of John Colby
Sent: Thursday, June 17, 2021 2:15 PM
To: Access Developers discussion and problem solving <accessd at databaseadvisors.com>
Subject: Re: [AccessD] Access 2010 or later - storing and referencing code in libraries

Read this:

https://docs.microsoft.com/en-us/openspecs/microsoft_general_purpose_programming_languages/ms-vbal/a09fd48e-abed-4da8-8c4c-a110bf4ef6b6

Hidden attributes in modules
<https://docs.microsoft.com/en-us/openspecs/microsoft_general_purpose_programming_languages/ms-vbal/a09fd48e-abed-4da8-8c4c-a110bf4ef6b6>

Notice specifically Public Creatable
TABLE 1

Instancing Mode

Meaning

Attribute Values

Private* (default)*

The class is accessible only within the enclosing project.



Instances of the class can only be created by modules contained within the
project that defines the class.

VB_Exposed=False VB_Creatable=False

Public Not Creatable

The class is accessible within the enclosing project and within projects
that reference the enclosing project.



Instances of the class can only be created by modules within the enclosing
project. Modules in other projects can reference the class name as a
declared type but can’t instantiate the class using new or the CreateObject
function.

VB_Exposed=True VB_Creatable=False

Public Creatable

The class is accessible within the enclosing project and within projects
that reference the enclosing project.



Any module that can access the class can create instances of it.

VB_Exposed=True VB_Creatable=True





On Thu, Jun 17, 2021 at 12:50 PM Jim Dettman via AccessD <
accessd at databaseadvisors.com> wrote:

> John,
>
>  Don't know the answer to this right off, but the docs/comments I find all
> say that the VB_Creatable attribute is ignored with VBA.  I know you said
> you've done this in the past, but all these docs/comments are more recent
> and I wonder if a change might have been made, or if something else that
> was
> done cut the ability to do that off.
>
>  But I did find this, which I think you'll find interesting and may be of
> help:
>
> How to use a class (object) from outside of the VBA project in which it is
> declared
>
>
> https://docs.microsoft.com/en-us/previous-versions/office/troubleshoot/offic
> e-developer/set-up-vb-project-using-class
> <https://docs.microsoft.com/en-us/previous-versions/office/troubleshoot/office-developer/set-up-vb-project-using-class>
>
>   Using a helper function, it shows how to instantiate a class in another
> project.
>
> Jim.
>
> -----Original Message-----
> From: AccessD On Behalf Of John Colby
> Sent: Thursday, June 17, 2021 12:16 PM
> To: Access Developers discussion and problem solving
> <accessd at databaseadvisors.com>
> Subject: [AccessD] Access 2010 or later - storing and referencing code in
> libraries
>
> I need assistance creating a library file, using Access 2010, which
> contains CREATABLE classes.
>
> If you export a class made in Access 2010 using the 2007 file format, in
> the header it will have a set of properties looking like this:
>
> VERSION 1.0 CLASS
> BEGIN
>   MultiUse = -1  'True
> END
> Attribute VB_Name = "dclsFrm"
> Attribute VB_GlobalNameSpace = False
> Attribute VB_Creatable = False
> Attribute VB_PredeclaredId = False
> Attribute VB_Exposed = True
> Option Compare Database
> Option Explicit
>
> Back in the day, I would change vb_Creatable as follows:
>
>   Attribute VB_Creatable = True
>
> What this does is allows the class to be stored in an MDS file, then
> reference the MDA and use the class from there.  The vb_Creatable
> propert specifically allows the class to be instantiated using "Dim MyCls
> as new clsXYZ"
>
> Without the file having the VB_Creatable = true, the class can be seen
> but cannot be instantiated.
>
> So... I export the class, I edit the file in a text editor setting
> vb_Creatable = true, I reimport it back into the file.  If I export it back
> out, the property has been changed back to VB_Creatable=False.
>
> And of course, if I reference the library, and try to instantiate the class
> it fails to compile.
>
> Understand that I have the exact same code in an old MDA file.  If I open
> that mda file WITH Access 2010 and export the class to a text file the
> vb_Creatable is in fact True.
>
> I am utterly failing to create an MDA file in 2007 file format which allows
> me to do this thing.  I am unable to even truly create an MDA file.  I can
> call it .MDA but the lock file will be .Accdb.
>
> I can create an Accda file but it too fails to retain the vb_Creatable =
> true, and any file stored in said file will not instantiate.
>
> This is really basic stuff.  I used it for a decade to store my framework
> and dozens of classes in C2DbFramework, reference the mda file and used "as
> new" syntax.  I no longer can do this.I can't find any reference out on
> google to doing this.  Lots of stuff about these hidden properties of
> classes, most of it wrong, none of it discussing using classes from a
> library file.
>
> Help me Obi Wan...  Is there an Obi Wan left amongst us?
>
> --
> John W. Colby
> Colby Consulting
> --
> AccessD mailing list
> AccessD at databaseadvisors.com
> https://databaseadvisors.com/mailman/listinfo/accessd
> Website: http://www.databaseadvisors.com
>
> --
> AccessD mailing list
> AccessD at databaseadvisors.com
> https://databaseadvisors.com/mailman/listinfo/accessd
> Website: http://www.databaseadvisors.com
>


-- 
John W. Colby
Colby Consulting
-- 
AccessD mailing list
AccessD at databaseadvisors.com
https://databaseadvisors.com/mailman/listinfo/accessd
Website: http://www.databaseadvisors.com