SharePoint APP with C#
Make it possible to dev SharePoint Hosted Apps with C# (csom) just like JS.
Thanks for your feedback! Although we appreciate your time and effort to give us this feedback, it’s not something we’re planning to do right now. Using C# based customizations in SharePoint Online in safe way was possible in isolated scenarios with Sandbox solutions, but this capability has been removed. SharePoint hosted apps are hosted in the SharePoint and there’s no way to provide code level isolation which would be required for these scenarios.