Limitations of Global Templates and Excel Add-ins (.xla Files)
The information in this topic applies only to the specified Visual Studio Tools for Office projects and versions of Microsoft Office.
Microsoft Office version
For more information, see Features Available by Application and Project Type.
Documents, workbooks, and templates might not work correctly as global templates or Microsoft Office Excel add-ins (.xla files).
If a Microsoft Office Word template has managed code extensions, the project assembly is not called if the template is attached as a global template or loaded from the Startup directory of Word. In addition, the document does not recognize the format of a template that is part of a Visual Studio Tools for Office solution.
Excel Add-Ins (.xla Files)
There is no Visual Studio Tools for Office project for creating an Excel add-in (.xla file). It is possible to save a workbook as an .xla file, but it is not a supported operation and is not recommended. If you save a workbook that has managed code extensions as a Microsoft Office Excel Add-In (*.xla) file, you can select it in the Add-Ins dialog box to apply to another workbook. In some cases your code will run in the target workbook after the add-in is applied, but such use of the Visual Studio Tools for Office solution is not supported.