Sharepoint itemupdating beforeproperties null gridview1rowupdating not working
Continue debugging, and the add-in will finally render the full-page experience.
A good alternative is to add a condition on the actual update logic: only perform an update if there's a change.
If you attempt to uninstall the add-in while debugging, you will notice that you receive a permission denied error.
This occurs only while side-loading the add-in, which is what Visual Studio does when you deploy using F5.
The code to prevent recursively calling the remote event receiver uses a Event Firing Enabled method.
You can do this by expanding this sample like this: to the existing Item Added RER an Item Adding and Item Updating RER has been added.