Will an application run when only a newer framework is installed - c#

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?

Related

Why .net 4.6.1 needed when in target framework is 4.5.2

I have one friend with Windows 7 OS (x64). For this OS .net 4.6.1 is unsupported.
I have on my pc Windows 10 (x64) with install vs community 2015 and here all working fine.
So, when my friend is trying to launch my app he gets request to install .net 4.6.1.
In vs project "Target framework" field is ".NET Framework 4.5.2"
Crutches from Microsoft?
and what can i do for fix that?
From here:
The .NET Framework 4.6 is an in-place upgrade for all of the following versions of the .NET Framework:
.NET Framework 4
.NET Framework 4.5
.NET Framework 4.5.1
.NET Framework 4.5.2
An in-place upgrade means that if you install the .NET Framework 4.6 when any of the above versions of versions of the .NET Framework are installed on your PC, .NET Framework 4.6 setup will upgrade them and you will be left with only the .NET Framework 4.6 installed afterwards. In addition, any attempts to install older versions of the .NET Framework 4 family when the .NET Framework 4.6 is already present will result in .NET Framework setup blocking you from installing because it detects that a newer version is already installed.
The .NET Framework 4.6 is designed to be compatible with all applications created with any version of the .NET Framework from 4 to 4.6, but there are sometimes application compatibility issues that arise, such as an installer that tells the user that they must install the .NET Framework 4.5 even if the .NET Framework 4.6 is already installed. In cases like this, you might need to revert back from the .NET Framework 4.6 to an earlier version of the .NET Framework 4 family. To do that, you must uninstall the .NET Framework 4.6 and then re-install the earlier version of the .NET Framework from the .NET Framework 4 family.
Basically, it is prompting you to install 4.6.1 because it is the highest version that is compatible with your program that is targeting 4.5.2, and the target machine apparently doesn't have any compatible framework (4.5.2 or higher) installed.

How to have two project in .net solution one targeting 4.0 framework and other one 4.5 framework?

I have a module which is using .Net 4.5 features and our application works for XP users also. So I was thinking of moving this .net 4.5 dependent module to separate project. How can I have a solution which is having two projects targeting to different version?
Each project in a solution is targeting it's specific version of .NET, so there is nothing special to that, BUT you can NOT reference that project/module targeting .NET 4.5 from the .NET 4.0 project.
If you need to target .NET 4.5 for some module your main application must also target .NET 4.5, so if there is no way around that features you need to ditch XP support, which is IMO not a bad thing as XP is not a supported OS anymore.
IF that feature from .NET 4.5 is the async/await-feature you could use the Microsoft.Bcl.Async-package an keep targeting .NET 4.0...

.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.

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.

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

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.

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