Why is there no Microsoft.Win64 Namespace?

Question

We have a Microsoft.Win32 Namespace but is it guaranteed to work in 64-bit Windows environments? Is there an equivalent need to have such definitions for a 64-bit situation?

Answer 1

For the same reason we have 64 bit binaries stored in the system32 folder in 64-bit Windows.

Basically, that's because things in Microsoft.Win32 are not specific to 32-bit Windows. Why should they harm portability without any benefits?

Answer 2

.NET applications by default run on the framework which targets the architecture of the OS. So, if you're running 32 bit Windows, the .NET framework installed on the machine would be the 32 bit framework. All .NET applications running on this framework would then run in "32 bit".

If you're running 64 bit Windows then you're running a 64 bit framework but the IL that's running on top of the framework doesn't differ (by default) from that of the 32 bit IL.

So in short: it doesn't matter if you're running 32 bit or 64 bit Windows since the .NET framework abstracts that away from the C#/VB code.

The Microsoft.Win32 framework refers to the native APIs inside of Windows. Short of the really bad name that Microsoft has given it, it has nothing to do with 32 bit vs 64 bit Windows.

Incidentally, there are some things you can't do with the 64 bit version of the framework: for example, there isn't a JET database driver in the 64 bit framework.

Answer 3

"Win32" is the name of the platform (i.e. the core API set), regardless of the actual bitness of the OS. In other words, don't worry about it :)