What platform/technology would work best for a web app that has heavy client-side excel type operations?

Question

So, I am working on an app that needs heavy "cell" calculations in a web-based app. The client needs to be able to change values, even the formulas... calculate totals etc, all on the client side in basically a "spreadsheet".

These requirements are pretty strict :(

I am wondering if there is any library or any way to utilize Excel through a web page? Would Silverlight provide any benefit? One thing I was thinking about is that we need some of the same functionality on the client and server (formula calculating), so Silverlight would be great for the re-usability of our C#. Any help is greatly appreciated!

EDIT 1: ## It is not a public facing application.

Answer 1

Excel Web Services?

http://office.microsoft.com/en-us/sharepointserver/ha101054761033.aspx

Answer 2

Have you considered using Excel itself? Could be a particularly good option for a non-public-facing app.

You can embed .NET code into Excel, including a custom UI and web services calls, with a technology called VSTO. It gives you full programmatic control over cells, formulas, etc. Very cool!

Answer 3

You can try SmartXLS for .net.

It has Excel compatible calculation engine which can serve the calc work on the server end.

Answer 4

SpreadsheetGear for .NET will do it.

Here is an article by Deane Barker who had a similar question on stackoverflow.

Even Microsoft uses SpreadsheetGear for Excel based calculators on it's MSN Money site as you can see here.

You can find live ASP.NET samples here and download the free trial here.

Disclaimer: I own SpreadsheetGear LLC