Microsoft Office

Part VI
Programming Excel with VBA
n
n
n
n
To simplify access to worksheet functions. Custom worksheet functions stored in an add-in
don’t require the workbook name qualifier. For example, if you have a custom function named
MOVAVG stored in a workbook named Newfuncs.xlsm, you have to use a syntax such as the
following to use this function in a different workbook:
=NEWFUNC.XLSM!MOVAVG(A1:A50)
But if this function is stored in an add-in file that’s open, the syntax is much simpler because you
don’t need to include the file reference:
=MOVAVG(A1:A50)
To provide easier access. After you identify the location of your add-in, it appears in the Add-Ins
dialog box and can display a friendly name and a description of what it does.
To permit better control over loading. You can automatically open add-ins when Excel starts,
regardless of the directory in which they’re stored.
To omit prompts when unloading. When an add-in is closed, the user never sees the Save
Change In prompt because changes to add-ins aren’t saved unless you specifically do so from
the VB Editor window.
Creating Add-Ins
Technically, you can convert any workbook to an add-in. But not all workbooks benefit from this conversion.
In fact, workbooks that consist only of worksheets (that is, not macros or custom dialog boxes)
become unusable because add-ins are hidden.
Workbooks that benefit from conversion to an add-in are those with macros. For example, you may have a
workbook that consists of general-purpose macros and functions. This type of workbook makes an ideal
add-in.
These steps describe how to create an add-in from a workbook.
1. Develop your application and make sure that everything works properly.
2. Choose Office ➪ Prepare ➪ Properties to display the Properties panel above your worksheet,
enter a brief descriptive title in the Title field, and then enter a longer description in
the Comments field. This step isn’t required, but it makes installing and identifying the add-in
easier. To close the Properties panel, click its close button (X).
3. Lock the VBA project. This optional step protects the VBA code and UserForms from being
viewed. You do this in the VB Editor, using the Tools ➪ projectname Properties command (where
projectname corresponds to your VB project name). In the dialog box, click the Protection tab and
select Lock Project For Viewing. If you like, you can specify a password to prevent others from
viewing your code.
4. Save the workbook as an add-in file by choosing Office ➪ Save As and selecting Excel Add-
In (*.xlam) from the Save As Type drop-down list. By default, Excel saves your add-in in your
AddIns directory. But you can override this location and choose any directory you like.
NOTE
After you save the workbook as an add-in, the original (non-add-in) workbook remains active.
You should close this file to avoid having two macros with the same name.
774