can an x64 computer have both the x86 and x64 .net runtime installed?

Question

can an x64 computer have both the x86 and x64 .net runtime installed?

If so, how can I ensure that a program runs on the x64 runtime and not the x86 runtime?

Answer 1

Unless you tell it not to, VS should build an assembly that targets any CPU (ie. is platform agnostic). The .NET runtime will run the x64 version if it can, otherwise it'll run x86.

My understanding is that both x86 and x64 versions are installed on x64 machines (check out the Microsoft.NET folder under %WINDIR%, you should find both Framework and Framework64.

Cheers!