How can I upload a file via ASP.NET MVC and show a progress bar?
The beauty of ASP.NET MVC is that you can choose almost any out of the box upload component out there and use it without any problems.
This plugin for jQuery is a great choice and one that I use in my projects:Uploadify
Steve Sanderson put some examples on his blog awhile back that I found helpful. He has the source code available as well.
Uploadify is nice, but we can't use Flash, so we are using Darren Johnstone's file upload control:
ASP.Net File Upload/Download Module Version 2
http://darrenjohnstone.net/2008/07/15/aspnet-file-upload-module-version-2-beta-1/
It includes a progress bar dialog driven entirely with Javascript, and even has the capability to upload and download files directly to a SQL Server database.