In search of ... what version of .net a program is using

[barney]

Folk,

Is there a way to determine which version of .NET a given program is using?  Windows Explorer shows six (6) versions (four (4) major versions) installed on one (1) of my machines.  Regedit shows four (4) (three (3) major) versions (?!?  ).  Search provides much info on determining what is installed, but I've not found anything to show what version is actually being used by any given program.

[Curt]

I don't know the answer to your question, but it is my experience that if a software author "Prerequisites" .NET version 1.1 for his program, it will not settle with .NET version 2 or 3 or 4...
So you might easily need all of them, if you have old programs installed.

[barney]

Yeah,

That's the conundrum  .  I've got someone - not the author - asking me what version of .NET a program is using.  And I don't know how to find out.  .NET seems to be a lot like Java:  multiple versions required because of program(s) requirements.  And, apparently, no way to tell what version any given program is using unless you have the source and can read it  .  (Or, alternatively, you uninstall a version and the software no longer runs  .))
 
(And then there's the side issue that popped up when I compared the .NET folder to the registry entries  .)

[Ath]

A quick search found me this geeks-with-blogs answer
But this stack-overflow thread and this one have more and clearer information, IMHO

[wraith808]

No, you will rarely need multiple versions of .NET for one program especially a small one- the only case where this comes into play if a program uses assemblies (DLLs) that have requisite earlier versions.  And this becomes less of an issue in later versions as they are inclusive, i.e. 3 or higher, and you just install the latest version of .NET.

That said- on to the most reliable method I know.  The question that comes closest to what you want is what version of CLR is required.  This is a very intensive way to find out the information, so it requires a developer or a very technical person.

Install the .NET SDK (if not installed).  You should have it installed if you have visual studio installed.
Run ILDASM and select the application.  If from visual studio, you can open the visual studio command prompt and run it easily.
In search of ... what version of .net a program is using

Look at the Manifest Node.
In search of ... what version of .net a program is using

There are two places you can look- in the application resources, there should be an indication of the .NET version.  You can also look for the windows assemblies to see the versions.  I've highlighted both below.
In search of ... what version of .net a program is using

That should give you a pretty good indication of the highest version involved.

[Curt]

Speaking of .NET Framework: I have an "old" program requiring .NET version 1.1, but when I look at .NET 1.1 SP1's homepage, Win 7 is not listed as supported (support ended with Vista). So, what do I do, to run an old program requiring just .NET 1.1 on my W7: install it (.NET 1.1 SP1) anyway and hope for the best?
 

edit:

...  I've got someone ... asking me what version of .NET a program is using. 

-barney (June 07, 2012, 01:21 PM)

You are on DC, and "we" have many programs laying around. If you could tell what program and version, you might get surprised...