Question

What are any cross-platform compatibility gotchas when running Silverlight 4 apps both on Mac and Windows?

I’d like to believe that any program whatsoever written for Silverlight will magically run the same on Mac and Windows, but I find it very hard to believe that this is the case.

Answer 1

I have run across a couple:

• The WebBrowser and WebBrowserBrush work differently. On Macs, the underlying rendering engine is WebKit/Safari, while on Windows it’s IE.
• For out-of-browser apps, be careful about hard-coding any assumptions about the location of the My Documents folder. The documents folder to which OOB apps have access on macs is /Users/<username>/Documents.
• Any COM+ automation/interop obviously won’t work on the Mac at all.

Other than that, the runtime is pretty well-supported on the Mac and things do generally run the same between those platforms.

It is worth pointing out however that Microsoft seems to be changing their strategy with respect to pushing Silverlight as a cross-platform runtime. Silverlight 5 has a few features that almost certainly will be windows-only (P/Invoke comes to mind), and early reports are that Silverlight will find a home as the managed-code runtime for Windows 8.