friend can't run progs made with .net 4.5 on his XP machine

[kyrathaba]

I'm trying to collaborate with a friend on an idea for an app. Im building on a Win 7 machine using C# on top of .Net 4.5. He's running WinXP and gets a Not a valid win32 app message when he tries to run my program. Even when I use the x86 build configuration. I think it's because .Net 4.5 is for Vista forward (per Stackoverflow.com). Any solution so he can run my progs?

[Shades]

Besides upgrading the OS, not really. See MSDN article or this even more devastating one from Channel9.

I did more reading, and it might be so that you can compile your .net 4.5 code in Mono, and the result should still work on XP. That still leaves the question: do you want to have such a mix-n-match of IDE's on your build PC?


* edit: added Mono suggestion

[Renegade]

Shades is right. XP won't run 4.5. Upgrade OS, or downgrade required .NET version.

[kyrathaba]

Is there a relatively painless way to downgrade,  or would I have to manually uninstall 4.5, download 2.0, and install it?

[Stoic Joker]

Is there a relatively painless way to downgrade,  or would I have to manually uninstall 4.5, download 2.0, and install it?

IIRC It should just be a (.NET dependency version) dropdown menu (which defaults to the highest available) in the project creation wizard. In the few times I've gone that (C#) route I always pick the oldest version that will give me the features I'm after. How to change it after the project is created I've not a clue.

[kyrathaba]

Is it possible to install 2.0 alongside 4.5 and then tell Visual Studio Express which version to use in a given project?

[Stoic Joker]

Is it possible to install 2.0 alongside 4.5 and then tell Visual Studio Express which version to use in a given project?

I don't know. I'd assume that 2.0 would have already snuck in there with one of the MS chronically semi-forced Windows updates. But MSVS Pro/Std never seemed to care what was installed, it just listed all the currently available version options.

[Shades]

From this article/blogpost I gather that it might work to have two very different versions of .net installed on your build PC. I'm not so sure how well the "targeting" will work, though.

[kyrathaba]

Aha. I already had 2.0.  I just went to the Application tab under Project Properties and specified 2.0 instead of 4.5.

[Ath]

.Net 2.0, 3.x (avoid using that version btw) and 4.x can happily coexist on a single system. When installing 4.5 on a system where 4.0 already exists, it will be upgraded to 4.5. (Win Vista and later, as said above)
.Net 4.5 is fully backward compatible down to 2.0, except for the new/improved features and, hopefully, for all the bugs in these previous versions

[kyrathaba]

SOLVED.

Thanks, all.