My first attempt was to just register for the events directly from Silverlight and go, but that didn’t work. If I could make it work, surely Microsoft would have done the same thing and just included it in the runtime (or someone else would have tried it and posted it on the Internet). I started looking into this approach a bit, but didn’t hold out a lot of hope. And I got to thinking – Firefox on the Mac (newest versions) supports HTML5 drag-and-drop via Javascript – why can’t I use that to make this happen? Way back in the beginning of the project, we were discussing the technology we would to build this (and yes, this was before the PDC 2010 keynote about the future of Silverlight and HTML5 support at Microsoft), and we had marked down that one benefit of HTML5/JS/CSS was that we could support file drag-and-drop on all the Mac browsers, not just Safari (as Chrome/Firefox on the Mac are HTML5 browsers that support that).

A few weeks before release, my project manager comes to me and says – “the client says they really need file drag-and-drop to work on Firefox on a Mac – can you make it happen?” At first, I said “no,” but then I started thinking about it a bit further. On a Mac? Well… there’s stuff you can do to make it work on Safari ( ), but we weren't able to find anything that would work on Firefox or Chrome. On all the Windows browsers, “it just works”.

Case in point: Silverlight 4 file drag-and-drop. Sometimes, the great things just don’t quite work out like we hope. I can use a real strongly-typed language on the client, get full data binding support, great Intellisense from Visual Studio, and oh yeah - WCF 4 RIA Services is *really nice*.

I can do real transparency and rounded corners without having to cut 500 images and overlay DIVs in a slick way to achieve the visual effect the designer is looking for (and then test it on every browser/platform combination). I don’t have to worry about the wacky HTML differences that are IE 6 and how they differ from IE 9, Firefox, Chrome, and Safari. Why? Because it works pretty much the same on all the supported environments and browsers. Silverlight is great for building rich cross-browser web applications, especially for internally-facing applications where it’s ok to require the installation of the Silverlight runtime. Tl dr: The code in this post supports file drag-and-drop in Silverlight 4 on Firefox on Mac OS X (as well as Safari on OS X, though that's with JS already available on the Internet).

Installing silverlight on mac firefox