if you are creating an application on a PC with .NET 4 (first release) and let it run on a second with the lastest .NET 4 Version or the first pc was update to the lastest version of .NET 4 without recompiling it. Then the application still works.
How that works?
kind regards
Newer Version of the .Net Framework are just adding functions and keeping the "old" functions the same.
If you install newer versions of the .Net Framework they include the older versions.
Related
I'm working on a C# Code that has as Targeted Framework .NET 4.6, and I'm trying to troubleshoot some issues that occurs during the execution.
That code is running on some clients, that has a .NET 3.5 Version.
My question is, does .NET 4.6 supports retro-compatibility, and if so, should it be wiser to have an aligned Framework versions (Target Version same as Client Version)??
TL;DR: Basically, you can run old on new, but not new on old.
DotNet 4.6+ is backwards compatible in the sense, that you can run an App built with DotNet 3.5 etc. But you cannot run an app built with DotNet 4.6+ while using an older installed framework eg. 3.5 or others. Take it this way:
Imagine you have a windows 10 computer and you want to install an app built for windows 8 or even XP and older. Modern windows has the compatibility layers, necessary to run or install the program.
Now what you/your clients are doing is basically taking an app specifically designed for windows 10, and trying to run it on Windows XP or 95 etc. That won't work as the compatibility layers are not in place to support the "future". No one can foresee the new features and API's that they might add, so the app is incompatible with older Windows.
If you are targeting .NET 4.6, then target .NET 4.6.
Do not expect your code/app to be compatible with anything lower, and if you do need it to be, you have to target that specific version. Which has its own draw-backs as the newer methods / ways of doing things and many libraries you could be using do not apply/are not compatible.
You can either update everything to use 4.6 or higher, or switch your codebase to target 3.5 and live with the drawbacks.
From Backward Compatibility
The .NET Framework 4.5 and later versions 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 and later
versions.
In your case app is built on .Net Framework 4.6 and the platform on client machine is 3.5 version. There might be some issues because app requires newer version than platform it runs.
.NET Framework version 4.6 was included with Windows 10 from version 1507 and .NET Framework version 4.6.2 was included with Windows Server 2016. If your clients are running either of these versions of Windows or newer, you won't have to install anything to run your .NET Framework 4.6 app, and it won't be running on .NET Framework 3.5 even if you do have it installed.
If you're using an older version of Windows than that and don't have .NET Framework 4.6 or newer installed, I wouldn't expect it to run at all.
I have a legacy WPF application where I had to do some adjustments and which must be compiled to .NET 4.0 (because it is running on some WinXP production machines - nicely isolated, don't worry about that) and .NET 4.8 (Win10/11). I joined the two branches and upgraded them to a solution with multi-targeting SDK projects (NET40;NET48), made sure the PDBs are still in native format and the target platform x86 - everything works fine on my machine. But on these production machines a dialog appears informing me that the application depends on .NET 4.8 and asking me whether I would like to install it (which of course is not possible - .NET 4.8 cannot be installed on WinXP). When I decompile my .NET 4.0 executable I see it really is a NET40 application and x86 compiled. Any ideas?
You could try to remove the sku optional attribute from the app.config file.
See: https://learn.microsoft.com/en-us/dotnet/framework/configure-apps/file-schema/startup/supportedruntime-element
If I update from .net 4.5 to .net 4.8 when i compile my project. Does that introduce a risk that the clients cant run the dlls?
Do all users have to upgrade to .net 4.8 on their machines or are the .net version backwards compatible? They have all been able to run the app when it was compiled with .net 4.5.
What im trying to ask is if i risk that some clients wont be able to run the app by upgrading the Target Framework when building it.
This is from 4.5 to 4.8.
Does that introduce a risk that the clients cant run the dlls?
Yes
Do all users have to upgrade to .net 4.8 on their machines
Yes, if they do not already have it.
are the .net version backwards compatible?
Yes, they are backwards compatible, meaning a user with .net 4.8 can run programs written for .net 4.5 with no issue. Not the other way around.
What i'm trying to ask is if i risk that some clients wont be able to run the app by upgrading the Target Framework when building it.
They should have .net 4.8 installed since it is bundled with windows 10 1903 and later. See versions and dependencies. All older versions of windows 10 is end of life. The only exceptions are windows server 2019/2016.
Even if your client lacks .Net 4.8, windows should simply ask if they want to install .net 4.8, so it should be very easy to do as long as the users have permission to install things on their computers.
Hello friends i need an explanation regarding .NET framework pre-requisite while installing the published application in the target machine.
As java is downward compatible, by which i mean that if i have installed java v1.6 and if the application is developed using java v1.5 (i also mean that only classes and packages available in 1.5 are used to build the appln.)
I am sure that the application developed will definitely run by installing the latest or higher versions of jre or j2se.
Similarly in the case of .NET platform suppose if i develop my application using .NET framework 3.5 and in the target machine i have installed .NET framework 4.0 (the latest) even then it prompts to install the .NET framework 3.5 why is this so?
The real time example is i have downloaded and tried installing MySQL workbench and also installed .NET framework 4.0 But it still asks to install the .NET framework 3.5 before running the MySQL installation.
My question is does .NET framework is downward compatible as java or .NET?
Version Compatibility in the .NET Framework:
The .NET Framework 4 is
backward-compatible with applications
that were built with the .NET
Framework versions 1.1, 2.0, 3.0, and
3.5. In other words, applications and components built with previous
versions of the .NET Framework will
work on the .NET Framework 4.
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.
If your application or component does
not work as expected on the .NET
Framework 4, use the following
checklists.
For .NET Framework 2.0, 3.0, and 3.5 applications:
Check .NET Framework 4 Migration
Issues for any changes that might
affect your application and apply the
workaround described.
If you are recompiling existing source
code to run on the .NET Framework 4,
or if you are developing a new version
of an application or component that
targets .NET Framework 4 from an
existing source code base, check
What's Obsolete in the .NET Framework
for obsolete types and members, and
apply the workaround described.
(Previously compiled code will
continue to run against types and
members that have been marked as
obsolete.)
If you determine that a change in the
.NET Framework 4 has broken your
application, check the Runtime
Settings Schema to determine whether
you can use a runtime setting in your
application configuration file to
restore the previous behavior.
If you encounter an issue that is not
documented, file a Microsoft Connect
bug and contact netfxcf#microsoft.com
with the bug number.
Yes, .Net 4 framework is backwards compatible with applications built on previous versions of .Net. You can see this link on MSDN for more info.
If you have .Net 3.5 or .Net 4 installed and a third party still requires either (or and older version) then the installer is not checking the correct prerequisite install conditions.
I have winforms application. When I look at the references they are all .net 4 (same as the application) apart from one which says v2.0. I can run the app locally and use functionality from the .net components but as soon as I take the app to another machine it wont fire up. Apparently this hapens when references cant be found.
Im very confused as to why this would work locally. I have checked the GAC and only .net 2.0 versions exist for the referenced dlls.?..
What are the rules around rererencing dlls from older versions on .net?
It is perfectly fine to have the two versions of the framework running on the same machine. Are both .NET 2 and .NET 4 installed on the second machine you are testing on? I suspect that they are not.
Yes you can reference .Net 2.0 dlls from .Net 4.0 project.
You might be referencing only .Net 2.0 dlls but your target framework might be .Net 4.0, which might not be available on your other machine.
To correct this:
Open your project properties.
Set Target framework to .Net Framework 2.0 or 4.0.
If you set it to 4.0, you must have 4.0 installed on the machine you want it to run on.
The quickest way to see which versions are installed on a machine:
open VS command prompt and type clrver. (Ofcourse you'll need .Net SDK)
To see which framework your app uses type clrver
you can get for your application from task manager (in process tab, click View->select columns->check PID)
Starting .NET 4.0, your app can target multiple frameworks in different AppDomains in the same process.
Remember that the framework that your application is determined automatically, but you can override this default behaviours. One way to do this is what I described above.
Note that the GAC location has changed between .Net 2.0 and .Net 4.0. You most likely have both versions installed on your machine and you have looked at the 2.0 GAC.
The second machine most likely does not have 2.0 installed, hence it fails running.