Using Add-In Functions

The previous parts of this blog show you how to create add-ins; it's time now to use them.  To do this, you must link to the add-in.

Using Add-In Functions in Excel

To add a reference for an add-in that you've created, show the Excel options dialog box:

Using Excel 2010	Using Excel 2007

You can now go to the Add-Ins dialog box:

To show the Add-Ins dialog box:

You can now choose the add-in(s) that you want to load:

Tick each add-in that you want to load (here we've ticked WiseOwlCode).

You can now use any of the functions in your add-in within any Excel workbook (this will be true even after you exit Excel and go back in):

 

Here we've used functions to return people's full names, the path to where files are stored and whether particular worksheets exist or not.

Using the Function Wizard to Include Functions

You'll find it easier to get at functions if you use the function wizard:

Click on this tool to insert a function.

You can then select the User  Defined category (as shown here) to display a list of all the functions in your add-in:

When you choose User Defined, you can see the functions you've written and shared.

Using Add-In Functions and Procedures in VBA 

To use a function in an add-in, first include the add-in in Excel (as shown above) , then reference it:

We're writing a module in a new workbook, and our DoesWorksheetExist function doesn't seem to exist.

First go into the References dialog box: 

Select Tools --> References from the menu in the VBA code editor.

Now tick the box next to the add-in whose code you want to use:

Tick (in this case) the WiseOwlCode application.

You can now use any code in your referenced add-in:

That's more like it! The DoesWorksheetExist function is in a referenced application.

I'd recommend qualifying the function name with the object library to which it belongs:

If you type in the name of the add-in project, the code completes automatically.