Implement functionality of google drive in asp.net website

See more:

C#

ASP.NET

Google-Docs

We need to implement functionality like google drive. We tried to used google-drive api and we are able to upload and download the document but we also need that user can view the document in the browser and edit it if he have the permission. Something like this 

collaboration tool allowing multiple editors at the same time on a document

Some option we already tried but failed due to there limitations:-
1. Integration of WebDav
2. Viewer.js and webodf.js

Please provide your suggestion and it will really appreciable