what to look out for when migrating .net apps to Windows 7, 64 bit

Question

we are migrating our desktop to windows 7, 64 bit (from 32bit Windows XP). We have a number of Winforms C# applications and are trying to figure out what to look out for in this upgrade. Is there any suggestions or good resources to look at from a developer point of view on what to look out for to make this a smooth transition?

Answer 1

.Net behaves more or less the same on 32Bit and 64Bit OS'es, so there is not much to worry about there AFAIK.

The main things you must be aware of are changes in the OS itself:

• The registry is changed, so if you read or write registry settings you may have to modify that code
• Some file locations are changed. You have Program Files for 64-bit apps and Program Files (x86) for 32-bit apps for instance. Also some other system folders have moved.
• UAC may cause trouble. You must test for this
• Your program may not have rights to write to some locations on the file system or in the registry. You may have to ask the user for permission or even require the user to run the application as an Administrator in the worst case.

Those are the changes I can think of at the moment. In most cases your app will run just fine on both OS'es.

Answer 2

If your app pokes around in the OS portions of the Windows registry or in the Windows system directory or program files directory, you may run into issues when running your 32 bit app on a 64 bit Windows OS.

The vast majority of applications don't muck around in these core system areas and run just fine in a 64 bit Win OS.