IIS7: Why can't i Choose v3.5 .net Framework? - c#

The only choices for the application pools are .net 2.0 or 4.0, but my machine is running on 3.5.
I am currently getting a
system.platformnotsupportedexeception
in an app that i built, and i think it might be related to this issue.

Keep in mind, there is no 3.5 version of the .NET runtime - only a 3.5 version of the .NET Framework. The CLR itself is either 2.0 or 4.0. Why they have weird versioning is beyond me (I guess there were no runtime modifications to support the 3.5 framework), but the framework versions are different than the runtime versions.

.NET 3.5 has the same base runtime as .NET 2.0. So in your case, selecting 2.0 is correct.
See this similar question.

Related

Will an application run when only a newer framework is installed

I cannot seem to find an answer to my question, so I just ask it here:
Say, I have an application built for .Net framework 4.62.
Will it run on a server that only has 4.7 installed?
(besides some older frameworks of course)
Or do I need to install every targeted framework?
The .NET Framework 4.5 and its point releases (4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, and 4.7) are backward-compatible with apps that were built with earlier versions of the .NET Framework. In other words, apps and components built with previous versions will work without modification on the .NET Framework 4.5.
For more info, you can refer to this link: https://msdn.microsoft.com/en-us/library/ff602939(v=vs.110).aspx
In other words, it should work fine.
An application built for 4.6.2 will work on any platform with at least 4.6.2. installed, so 4.7 is okay too. Those versions are backwards compatible.
The above is true for all applications built for .NET 4.0 and higher. For some older versions (in the .NET 2-3.X era) you need to have installed a .NET Framework version up to 3.X, since that .NET Framework version still use the old .NET 2 CLR. From .NET 4 on, it is an in-place update.
The short answer is yes, since the .net framework is backwards compatible.
See more info here:
What is .NET framework backward compatibility?

.Net 4.0 targeting on windows 8.x

I'm a bit confused about targeting .net 4.0 app to run on windows 8.x. In my understanding, windows 8.0 comes with 4.5 and windows 8.1 comes with 4.5.1. So my question, if I build a WinForms or WPF client app targeting c#/.net 4.0 (in Visual Studio Project settings) and of course only using .net 4.0 features (i.e, no features from .net 4.5.x), then will this app run fine on windows 8.x without having install .net 4.0 framework (that is, only relying on what comes installed with OS)? Basically, I'm trying to avoid forcing end user to install .net 4.0 framework on their machine before running the app.
Looking at DLLs properties of various Microsoft DLLs (e.g., System) they show same runtime version when targeting either .net 4.0 or .net 4.5.x --> v4.0.30319. So my understanding here is that 4.0 and 4.5.x are targeting same clr runtime version So, my .net 4.0 app should run fine???
From ref here (http://msdn.microsoft.com/en-us/library/bb822049%28v=vs.110%29.aspx), it says .net 4.0 can't even be installed on win8.x.
In my tests, targeting .net 4.0 and running on clean install of win8.1 seems to work fine (without having to install anything else) but looking for advice on gotchas.
Thanks.
Note that the .NET framework is intrinsically backwards compatible - .NET 4.5 will execute .NET 4.0 code just fine. This can be seen even within a solution in that a .NET 4.5/4.5.1 project can reference an older .NET project without incident. This includes .NET 4.0, as well as earlier versions.
In addition to the backwards compatibility, .NET 4.5 does run on the CLR 4.0 - 4.5 is simply a library and compiler expansion.
Possible gotchas
This emphasis on backwards compatibility is why we almost never see functions disappear from the .NET Framework, just get marked [Obsolete]. it's a good idea to check if any functions you use have become Obsolete, though this is rare and such functions usually continue to work as expected.
Windows 8 does NOT like Drive mapping, and will demand that you use UNC paths if you application touches any networks drives.
Windows 8 can be far more aggressive with requiring Admin privileges to run, up to and including needing to explicitly start VS as admin when trying to compile a program which outputs to C:\Program Files\...
Final note: ALWAYS test your application on the targeted platform before releasing to users.
Per this question:
.NET Framework 4.5 was released on 15 August 2012., a set of new or improved features were added into this version. The .NET Framework 4.5 is only supported on Windows Vista or later. The .NET Framework 4.5 uses Common Language Runtime 4.0, with some additional runtime features.
I would say then that by virtue of having .NET 4.5 installed you will also always have .NET 4.0 installed. I don't think this should be an issue then!
From the link you posted:
Each new version of the .NET Framework retains features from the previous versions and adds new features.
Also from that link:
The .NET Framework 4.5 is an in-place update that replaces the .NET Framework 4 on your computer, and similiarly, the .NET Framework 4.5.1 4.5.2, and 4.6 Preview are in-place updates to the .NET Framework 4.5, which means that they use the same runtime version, but the assembly versions are updated and include new types and members.
So, if a system has 4.5, it will be able to run apps targeted for 4.0 as well. The fact that some versions cannot be installed most likely only means that they are already included from the start.

Deploying a .net 4.0 application

I have an application built with .net 4.0 and uses WPF
My users have Windows 7 with default .net 3.5 installed.
My application cannot be downgraded to .net 3.5 and I want to avoid users from going through the process of downloading and installing .net 4.0 which is about 40MB (Even with silent install).
Since my application is a small one, is there a way to deploy it with only the required .net 4.0 libraries? and thus avoiding the installation of the entire .net 4.0 framework
If this is not possible, is there a way to execute the .net 4.0 app in a .net 3.5 environment?
If this is not possible, is there a way to execute the .net 4.0 app in a .net 3.5 environment?
No. Basically you really need to get the environments aligned. You say your application cannot be downgraded to .NET 3.5 - presumably that's because you're using something which is specific to .NET 4.0. It stands to reason that you can't then execute that in an environment which doesn't have .NET 4.0.
You need to decide which is more painful - changing your app to target .NET 3.5, or asking your users to install .NET 4.0.

Assembly compiled in older .NET version running in newer .NET version, will behavior change?

I have an assembly that is compiled with .NET 3.5. I cannot recompile it in .NET 4.5 since it is used in other applications that are still running .NET 3.5. When I use the assembly in my apps that are running .NET 4.5 will the assembly be treated as if it is running in .NET 4.5 instead of .NET 3.5? I have a WinForms app and a WebForms app both in .NET 4.5. If there are changes in behavior between .NET 3.5 and .NET 4.5, with the assembly return the 4.5 results?
Usually .Net frameworks are backward-compatible, so executing an assembly developed in .Net 3.5 shouldn't be a problem on 4.5.
You should see: Version Compatibility in the .NET Framework
The .NET Framework 4.5 is backward-compatible with applications that
were built with the .NET Framework versions 1.1, 2.0, 3.0, 3.5, and 4.
In other words, applications and components built with previous
versions of the .NET Framework will work on the .NET Framework 4.5.
But there could be problems as well like the one mentioned in the article :
However, in practice, this compatibility can be broken by seemingly
inconsequential changes in the .NET Framework and changes in
programming techniques. For example, performance improvements in the
.NET Framework 4 can expose a race condition that did not occur on
earlier versions. Similarly, using a hard-coded path to .NET Framework
assemblies, performing an equality comparison with a particular
version of the .NET Framework, and getting the value of a private
field by using reflection are not backward-compatible practices. In
addition, each version of the .NET Framework includes bug fixes and
security-related changes that can affect the compatibility of some
applications and components.
The best way for you would be make sure your test cases pass after including dll from 3.5.

.NET Runtime 2.0 Error on .NET 3.5 application

My colleagues and I have some misunderstandings about the .NET runtime. I've written a WPF application (targeted for 3.5) that randomly crashes, and in the event log, we see .NET Runtime 2.0 Error Reporting as the source.
Just to confirm:
3.5 still runs on the .NET 2.0 Runtime (i.e., it's an extension of it), so an application targeting 3.5 will still show .NET Runtime 2.0 as it's error source.
When installing .NET 3.5 Framework, there's no way to not install .NET 2.0 along with it.
Am I right?
You are correct. There are, currently, 4 .NET runtimes (though the last is in beta).
1.0 Runtime, which was very buggy
1.1 Runtime
2.0 Runtime, which is used for .NET 2.0, 3.0, 3.5, and 3.5sp1, as well as Silverlight
4.0 Runtime - In Beta2, and soon to be released with VS 2010 and will be used by .NET 4.0
There is no way to install .NET 3.5 without the 2.0 runtime, since it uses that runtime, and is based on it.
You are correct on both points.
Yes, you are right. The .NET 3.5 Framework runs on .NET 2.0 CLR. Essentially the change is new assemblies (and new versions of .NET 2.0 assemblies) and new compilers.

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