The use of DirectInput for keyboard and mouse input is not recommended.[/quote]

Could anyone elucidate why this might be the recommendation? Are there serious drawbacks to using DirectInput for keyboard/mouse (I'll only be targeting PCs and possibly Windows 8 tablets). What makes the message loop/window procedure in Win32 or the events of .Net 4.5 more suitable?

So creating a game I hope to be able to compile and run as both Win32 and .Net 4.5,[/quote]
To use Win32, you need C or C++ (or other native language). To use .NET 4.5 you need C#. How exactly do you expect to do this?

I'm considering using DirectInput to handle all user input as it'll basically be unchanged across both.[/quote]
The code will have to change rather drastically in fact as the C or C++ interface to DirectInput (via COM) is superficially very different from the available managed wrappers that support DirectInput (SlimDX and SharpDX). The code won't directly compile at all.

I have a feeling you don't quite understand the distinction between Win32 and .NET. Win32 is a native C API, .NET is an implementation of the CLR. They are not equivalent technologies.

Could anyone elucidate why this might be the recommendation?[/quote]
DirectInput is deprecated and just sits on top of Win32 messages or RawInput, depending. So it's generally better just to use Win32 messages or RawInput. The only thing you'd really need DirectInput for is joystick support.

To use Win32, you need C or C++ (or other native language). To use .NET 4.5 you need C#. How exactly do you expect to do this?[/quote]

Through C++/CX for the .NET side of things. I'm entirely sure it's all possible yet, but I'm working on that side of it ATM and it seems to be going fairly smoothly... Is that not going to work?

The code will have to change rather drastically in fact as the C or C++ interface to DirectInput (via COM) is superficially very different from the available managed wrappers that support DirectInput (SlimDX and SharpDX). The code won't directly compile at all.
I have a feeling you don't quite understand the distinction between Win32 and .NET. Win32 is a native C API, .NET is an implementation of the CLR. They are not equivalent technologies.[/quote]

I might not be using the proper term here and may actually be referring to WInRT. But it all looks very similar to .NET to me... I wouldn't want to use a wrapper here either, I would want to interface directly with the library where at all possible for the clearest picture of what's going on.

DirectInput is deprecated and just sits on top of Win32 messages or RawInput, depending. So it's generally better just to use Win32 messages or RawInput. The only thing you'd really need DirectInput for is joystick support.[/quote]

Ah ha. OK, the recommendation makes sense then.

Through C++/CX for the .NET side of things. I'm entirely sure it's all possible yet, but I'm working on that side of it ATM and it seems to be going fairly smoothly... Is that not going to work?[/quote]
No.

C++/CX is C++ with some extensions to support accessing the new Windows Runtime (WinRT); it is primarily syntactic sugar for COM support. C++/CX produces native code as WinRT is a native code framework. You cannot mix managed and native code in a C++/CX project, so you cannot even combine it with C++/CLI. Using C++/CX -- like using C++ -- gives you a 100% native binary.

C++/CLI looks the same as C++/CX because Microsoft basically lifted the syntax. C++/CLI would let you produce managed code, but it isn't C++ -- it's a managed language, so at that point you may as well just be using C#. There is no point to ever using C++/CLI unless you are writing an interop library to expose a native API to managed code or the other way around.

I might not be using the proper term here and may actually be referring to WInRT. But it all looks very similar to .NET to me... I wouldn't want to use a wrapper here either, I would want to interface directly with the library where at all possible for the clearest picture of what's going on.[/quote]
Yeah, you're not. WinRT isn't .NET, it's not related to the CLR or managed code at all. Furthermore, you can't even use DirectInput for Metro apps in WinRT.

It sounds like all of your plans are based around an assumption of compatibility, when in fact the technologies you're all talking about are quite incompatible at varying levels. You should probably revisit your plan by determining what platform you want to target or what language you want to use and then doing some research into what is possible with that platform -- MSDN is an excellent resource, you should start there.