VSTO Excel: Fix COMException on Worksheet Activate
A COMException on Worksheet.Activate is a classic VSTO timing issue. Here's the reliable fix.
Kiroloss
Francis
Full-stack engineer specialising in C# / .NET, VSTO Office Add-ins, iOS & Android development, and web accessibility (WCAG). Passionate about clean code, accessible design, and building software that works for everyone.
10+
Years experience
2
Published apps
1
Book authored
A11y
Advocate
KF
What I Work With
Technologies, platforms, and methodologies I use day-to-day.
C# / .NET 8
ASP.NET Core MVC
VSTO Office Add-ins
iOS (Swift)
Android (Kotlin/Java)
Web Accessibility / WCAG
JavaScript / Angular
SQL / EF Core
Azure / CI/CD
Drupal CMS
Git / DevOps
Agile / Scrum
Mobile Applications
iOS & Android apps published on the App Store and Google Play.
St Mary & St John Bromley
Church community app for St Mary & St John Bromley congregation. Built for iOS and iPad.
App StoreSt Paul Coptic Orthodox Church
Digital home for the St Paul Coptic Orthodox Church Southern Diocese community.
App Store · Google PlayAll Apps on Google Play
View the full catalogue of Android apps published by Kiroloss Francis on the Google Play Store.
Google PlayAuthored Book
Beyond
Barriers
Barriers
Beyond Barriers
A book exploring how to overcome barriers in software development, career growth, and technology accessibility. Available internationally.
ISBN: 9798369456927
View on BokusFrom the Dev Blog
Fix: Angular ExpressionChangedAfterItHasBeenCheckedError
One of Angular's most confusing errors. Here's what causes it and how to fix it properly.
WCAG 2.2: How to Properly Label Form Inputs for Screen Readers
Placeholder text is NOT a label. Here's the correct way to label form controls for WCAG 2.2 compliance.
Work Together
Available for senior engineering roles, accessibility consulting, and Office Add-in development.