Setting platform target to x86 on my x64 laptop prevent some WPF types to load properly

Question

I have a x64 machine running Windows 7 64 bits. It seems I have a very weird situation since the beginning of the week.

If I build and run a WPF application with pla

Answer 1

Setting the platform target to x86 is going to cause your application to call x86 versions on unmanaged assemblies and run in WOW64 mode. See this article on platform target and this msdn page on WOW64. If you trace the static Grid constructor in Reflector, it looks like some thread initialization code calls an externed unmanaged function "RuntimeHelpers.PrepareConstrainedRegions()" which could be causing the problem (the StackPanel doesn't call this code). There's a bit of speculation behind this, but you might try running Windows Update to make sure you have the same updates as your coworker, and make sure you have all the VS/.NET updates out there as well.

Ultimately, unless you're calling some 3rd party unmanaged dll's from your code that are only available as x86 assemblies, you should probably leave the platform target as Any CPU so it'll run native on x86 and x64 platforms.

Lastly, if after running windows update you're still seeing the problem, if possible, update your coworker's PC as well and see if the problem crops up. If it does, there could be a bug in the WOW64 layer, and it'd be good to file a bug report with Microsoft.