Create application page on O365

Question

I have created an aspx page for login to O365. I then found a post saying you cannot have .cs code behind files on SharePoint that you should reference an assembly.

I am assuming the assembly in this case would be my project dll, but where do you add this assembly in O365?

Answer 1

In SharePoint online you cannot add any SharePoint Server Object model code. You have below options:

1. Convert the code to JavaScript,upload it to style library and create a page in Pages or SitePages library and refer javascript file in script editor/content editor web part.

2. Create SharePoint hosted app for the functionality(Javascript CSOM).

3. Create a Provider hosted App (Managed CSOM).

Update: The recommendation now a days is to use SharePoint Framework