How to enable uploading files by dragging and dropping them using asp.net?

One of my clients has requested the functionality of uploading documents by dragging and dropping them in the browser window. The website is being built with A开发者_Python百科SP.NET 3.5. I know of the 'dragdropupload' add-in for firefox, which allows dropping files on an upload control, but I also need it to work in Internet Explorer.

Does anybody know of a way to programmatically enable this? Or are there perhaps any third party controls available (preferably free/open source)? It is acceptable if it is only possible to drop the file on an upload control. I cannot use any browser extensions like Silverlight or Flash.

I don't think this can be done i IE without ActiveX, or Silverlight