ACC97: Using Lightweight Objects in Microsoft Access 97

• Microsoft Access 97

SUMMARY

Moderate: Requires basic macro, coding, and interoperability skills.

This article describes the concept of lightweight objects and provides a technique to create a lightweight switchboard form in Microsoft Access 97 that uses the Hyperlink properties of form controls to open other objects in the database.

NOTE: A demonstration of the technique used in this article can be seen in the sample file, FrmSmp97.exe. For information about how to obtain this sample file, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q175066
   TITLE     : ACC97: Microsoft Access 97 Sample Forms Available on MSL

MORE INFORMATION

Microsoft Access 97 introduces the concept of lightweight forms and reports, which are objects that do not contain a class module. One advantage of lightweight objects is that they are smaller and typically load and are displayed faster than objects with class modules. Another advantage is that they help decrease the size of your database because they do not require storage space for a class module. Possible disadvantages of using lightweight objects is that they do not appear in the Object Browser, and you cannot use the New keyword to create a new instance of the object.

When you create a new form or report, it is a lightweight object by default. Microsoft Access 97 only creates a class module for the object if you do any of the following:

• Add Visual Basic code to an Event property in the object.
• Open the object in Design view, and then click Code on the View menu.
• Set the HasModule property of the form to Yes.

You can convert an object with a class module into a lightweight object by setting its HasModule property to No, and then saving the object. Do so with caution, however, because once you save the object, its class module and any code it contains are deleted.

By using the Hyperlink property of command button controls, label controls, and image controls, you can create a lightweight switchboard form in your database that does not use any Visual Basic code or macros.

The following example creates a switchboard form that demonstrates the use of hyperlinks to open database objects:

1. Open the sample database Northwind.mdb.

2. Create the following new form not based on any table or query in Design view:

         Form: MySwitchboard
         --------------------------------------
         Caption: Main Menu
   

         Command button:
            Name: OpenEmp
            Caption: Employees Form
            HyperlinkSubAddress: Form Employees
         Label:
            Name: OpenCat
            Caption: Catalog Report
            HyperlinkSubAddress: Report Catalog
         Image:
            Name: OpenSales
            Picture: C:\Windows\Circles.bmp
            PictureType: Embedded
            SizeMode: Clip
            PictureAlignment: Center
            PictureTiling: No
            HyperlinkSubAddress: Query Category Sales for 1995
   
      NOTE: If you do not have the file C:\Windows\Circles.bmp, you can
      substitute another bitmap or graphic file on your computer in the
      Picture property above.
   
      Note that the HasModule property of the form is set to No. That is how
      you can tell this is a lightweight form.
   
   

3. Save the MySwitchboard form, and then open it in Form view.

4. Click the Employees Form button, the Catalog Report label, and the image control and note that each one opens the object specified in its HyperlinkSubAddress property.

REFERENCES

For more information about lightweight objects, search the Help Index for "lightweight objects."

For more information about class modules, search the Help Index for "class modules," or ask the Microsoft Access 97 Office Assistant.

For more information about the HyperlinkSubAddress property, search the Help Index for "HyperlinkSubAddress property," or ask the Microsoft Access 97 Office Assistant.