We have a C# project and in Visual Studio the according "Target framework" is currently set to ".NET Framework 4.5". We have a second client library (written in C++) that calls this C# library to do something. For some new features we want to use the framework 4.6.1+. But we don't worn that C# project directly.
So some question in mind:
Generally, if we upgrade "Target framework" to .NET Framework 4.6.1 and on the machines where our app is running the actual framework is pre 4.6.1 (e.g., 4.5). What will happen? Will it throw some exception when the app is started?
If we stick to .NET Framework 4.5 as the target version, is there an option to automatically use the latest version actually installed on the machine where the app is run?
Thanks.
on the machines where our app is running the actual framework is pre 4.6.1 (e.g., 4.5). What will happen? Will it throw some exception when the app is started?
It will not throw an exception when the app started... The only time it could throw an exception is if (and when) your library calls a method that exists in .NET 4.6.1 but does not exist in .NET 4.5... You will get a MissingMethodException, other than that everything should work fine.
Something you can do is inspect what is the .NET Framework that is being run in the process that loaded your library.
string version = AppDomain.CurrentDomain.SetupInformation.TargetFrameworkName;
You can do that at the very start of the method being called in the library. And if the .NET Framework is < 4.6.1 you can decide what to do... Show an error message, or change the behavior as to not call into some functions (and avoid MissingMethodException).
One more thing you can also do determine which .NET Framework versions are installed on the machine and make some decisions on what to do.
.NET Framework 4.5+ is backward compatible. If app will be 4.6.1, but OS will have 4.5 then application error is possible (no forward compatibility). Documentation about version compatibility says:
By default, an app runs on the version of .NET Framework that it was
built for. If that version isn't present and the app configuration
file doesn't define supported versions, a .NET Framework
initialization error may occur. In this case, the attempt to run the
app will fail.
Related
I have a clickonce application being tested on a virtual machine. This virtual machine is empty and my application requires .Net Framework 4.6.1 on the machine. Now, my application is able to install .Net 4.6.1 but I'm having a weird behavior after install. I'm receiving this message when the application is being open after the installation of .Net 4.6.1.
I added 4.6.1 on my prerequisite by following this guide. How to Create .Net Framework Prerequisites Entry in Microsoft Visual Studio 2015
Here's the message
When I try to run the setup again, the setup process goes through then it launches my application. It seems the setup cannot detect the framework installed right after it install it. Or something went wrong somewhere during the installation. Is there a way to handle this? Any suggestion will be appreciated. Thanks!
The error message says that your application requires CLR 4.0.xxxx. If you specify .NET 4.0 as requirement too ? Maybe you are trying to execute something developped with .NET 4.0 anyway. This could help you :
Backward compatibility and the .NET Framework 4.5 :
The .NET Framework 4.5 and its point releases 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.However, by default, apps run on the version of the common language runtime for which they were developed, so you may have to provide a configuration file to enable your app to run on the .NET Framework 4.5.For more information, see the Version compatibility for apps section earlier in this article.
source
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.
I'm pretty new to .NET and C#.
I recently took up the task of upgrading my application from .NET 4.0 to .NET 4.5 to keep up with other products in my team.
I would like to be able to run my application (which has several projects, some web projects based on ASP .NET and some standalone app projects (console application)) on .NET 4 and .NET 4.5.
After following instructions online regarding <supportedRuntime> Element to upgrade from .NET 4.0 to .NET 4.5 by changing the target run-time I realized that the compilation element's targetFramework attribute is now 4.5. I understand that this means the code will definitely work on .NET framework 4.5.
What if I have a set of nodes that are waiting for 4.5 upgrade which are still running .NET 4.0. I'm pretty sure that my changes would break the application.
So I did some research and after referring to some documentation online, I've removed the sku attribute from the supportedRuntime element in the *.config files of the projects in the solution. Though the version attribute of the supportedRuntime element is still v4.0 (CLR version). I hope this make the application run on both .NET framework 4.0 and 4.5.
But I don't really know much about the compilation element and its significance apart from what I read from ASP .NET configuration guidelines. Would leaving the targetFramework make sure that my applications work on both .NET 4.0 and .NET 4.5?
How can I make sure that my changes are compatible with both .NET 4.0 and .NET 4.5?
[Why not leave it as .NET 4.0 till the nodes have their .NET frameworks upgraded?]
You might wonder why I can't keep it as .NET 4.0 for now.
The aim is to upgrade to .NET 4.5. But the standalone script runs on a set of nodes that run on Windows Server 2003 that does not support .NET 4.5. I've got my system admin team to allocate another node with .NET 4.5 for this process alone. So for the time being I can't really completely upgrade my existing code. Until after I test my existing code on .NET 4.5 and configure deployment to those new nodes.
Thanks to that comment from #hvd which lit a bulb in my confused brain. Now I know how to proceed.
The versioning of the .NET Framework is distinct from the versioning of the runtime (CLR and jitter). Already the case in previous versions, .NET 2.0, 3.0, 3.5 and 3.5SP1 used runtime version v2.0.50727.
Much the same for the 4.0 branch, versions 4.0, 4.0.1, 4.0.2, 4.0.3, 4.5, 4.5.1 and 4.5.2 all use the same runtime version, v4.0.30319
The "sku" attribute was added to provide the CLR with an extra check to ensure that the correct framework version is present on the machine. And powers this feature, very desirable. Without it, your 4.5 targeted project will start just fine on a machine that only has 4.0 installed. But will tend to fall over on a pretty ugly runtime exception, usually caused by a missing type or method. Especially the changes in 4.5 were rather impactful, types were moved from one assembly to another to make the footprint of the framework smaller on portable devices. This question is a good example, very ugly to diagnose.
A good example of how this went wrong before is the EventWaitHandle.WaitOne(int) overload. Added in .NET 2.0SP2 (aka 3.5). A good idea, nobody knew how to use the WaitOne(int, bool) overload properly. But a breaking change without a corresponding change in the [AssemblyVersion] for mscorlib. Causing horrible problems, programmers used the overload with gusto but their programs failed when it ran on an older version of .NET. Kaboom with a MissingMethodException, leaving very little clue how a simple and common method could be missing.
Cold hard fact is that if you target 4.5 in your project and remove sku then you'll get to deal with this kind of misery. You have to target 4.0 to keep compatibility, very simple to do of course.
In fact, if you change framework version to 4.0 in project properties, you'll be sure that 4.5 assembly members (namespaces, classes, interfaces...) won't be visible during design time/development time. Or compiler will cry if you try to use a member from version 4.5.
This is possible the best way to be sure you're not going to use newer members not present in previous .NET Framework versions.
How can i make a 4.0 project have a 4.5 reference. In the unit tests, i cant build the solution and it's giving me this warning.
Warning 2 The primary reference "PR.Wallet" could not be resolved
because it was built against the ".NETFramework,Version=v4.5.1"
framework. This is a higher version than the currently targeted
framework ".NETFramework,Version=v4.0". PR.Wallet.Tests
.Net frameworks (v2.0 or higher) are not forward compatible. . You can't reference a .Net 4.5 assembly in .Net 4.0 project.
See: Version Compatibility in the .NET Framework
You may also see: Version Compatibility
The degree of .NET Framework support for backward and forward
compatibility is version-specific. The .NET Framework supports both
backward and forward compatibility for applications created using
version 1.1 only. It does not support forward compatibility in
applications created using version 2.0. In the context of the .NET
Framework, backward compatibility means that an application created
using an early version of the .NET Framework will run on a later
version. Conversely, forward compatibility means that an application
created using a later version of the .NET Framework will run on an
earlier version.
The .NET Framework provides a high degree of support
for backward compatibility. For example, most applications created
using version 1.0 will run on version 1.1 and applications using
version 1.1 will run on version 2.0. The .NET Framework also supports
forward compatibility for version 1.1 only. However, for forward
compatibility you might need to modify an application so that the
application runs as expected. Applications created with version 2.0
will not run on earlier versions of the .NET Framework. For both
backward and forward compatibility, a change to the .NET Framework
that helps improve security, correctness, or functionality might also
raise compatibility issues.
Sounds like you need to change the framework of the library. And since it is only a unit tests project, I don't see why you wouldn't.
In Visual Studio:
Right-click on your project
Select Properties
Select the Application tab
Change the Target Framework to the desired framework
If you are not seeing .NET Framework 4.5.1 as an option there, ensure you have it installed.
You aren't able to reference a 4.5.1 assembly in a project that targets 4.0 .
But ... you can call the method of a 4.5.1 assembly in a project that targets 4.0 by calling it dynamically, assuming 4.5.1 is installed:
var assembly= Assembly.LoadFrom(...);
var type = assembly.GetType(...);
var method = type.GetMethod(...);
var res = method.Invoke(null, args);
Note that there may be limitations to this approach, but I found it useful for calling Roslyn routines while still using VS2010.
There may be exceptions. Based on my own experience, for example, some libraries like TagLib-Sharp 2.2.0 (which you can download from NuGet) perfectly allowed me to reference its .NET 4.5 DLL just fine from .NET 4.0 (Client of Full Profile) project running on Visual Studio 2010.
Additionally, calling some method from aforementioned referenced .NET 4.5 DLL did not emit any warning or error, build process went fine though, including at runtime. However, some methods/functions have failed, so it's a hit and miss but remember that referencing .NET 4.5 DLL was succeeded. So the answers and general rules above about "forward compatability" context clearly have some exceptions like TagLib-Sharp under particular circumstances.
Just out of interest, if I built some code using the Enumerable.Distinct function which appeared in .Net 3.5 and then ran it on a machine with .Net 2.0 on it, what would happen?
The program will crash as soon as the assembly that defines Enumerable.Distinct (System.Core) is needed. However, you can make it work if you target .NET 2.0 and use LinqBridge instead of System.Core.
You will be able to compile a 3.5 Framework project and run it on the 2.0 Framework as long as you don't have any 3.5 Framework references. In your case, you are using Enumerable.Distinct which is in the 3.5 Framework references, so your application will fail.
.Net 2.0 won't understand the command because the library isn't there.
.NET 3.5 is essentially .NET 2.0 + some extra assemblies.
If those extra assemblies aren't installed, ie. .NET 3.5 isn't installed, then your program will fail to load those assemblies when needed.
If you have somehow managed to steer clear of using those assemblies, then presumably your program will function just fine, but I'd say that would be the exception to the rule. For your specific example, at the point where your program uses .NET 3.5 code for the first time, you would get an exception.
In short, make sure .NET 3.5 (SP1) is installed on the target machines.
Most probably your code will complain about .net 3.5 being not installed at the startup.
Simple,It will crash at aribitary points at where you used the .net 3.5 specific functionality.
But basic question ... why do you want to do that ?
If you have migrated a project from .net freamework version 2.0 to 3.5 and not using any feature of .net 3.5 does not represent a valid framework migration