This is a two part question. I need both parts addressed for a complete answer.
Part I
I have a .NET 4.5 desktop app and I'm wondering if I can deploy it to Windows XP if, within "Requirements" in the app's Installshield project, I tick the ".NET 4.0 Full Package is Installed" checkbox instead of the ".NET 4.5 Full Package is Installed" one.
I read here that:
You can compile an application for .NET 4.5 and run it on the 4.0 runtime – that is until you hit a new feature that doesn’t exist on 4.0. At which point the app bombs at runtime. Say you write some code that is mostly .NET 4.0, but only has a few of the new features of .NET 4.5 like aync/await buried deep in the bowels of the application where it only fires occasionally. .NET will happily start your application and run everything 4.0 fine, until it hits that 4.5 code – and then crash unceremoniously at runtime.
So I know what the ability of my app to run on Windows XP with .NET 4.0 depends on. Let's assume for this question that my app won't crash as described in the above quote.
Part II
I also need to know what effect choosing ".NET 4.0 Full Package is Installed" instead of ".NET 4.5 Full Package is Installed" will have when installing the app onto a machine with .NET 4.5, but not .NET 4.0, installed. Will the Installshield installer see the installed .NET 4.5 package as .NET 4.0 and thus not complain? Or will it be picky and block the app's installation since specifically .NET 4.0 is not installed?
First thing you need to do is change the Target Framework version of your projects from 4.5 to 4.0 and rebuild. If you used any 4.5 specific feature then you'll now find out. You'll need to fix errors.
Part 2 is a non-issue, .NET 4.5 is a replacement for .NET 4.0. The installer is not going to uninstall 4.5 first so it can install 4.0, that would break all existing .NET apps on that machine.
Related
In my school they use VS 2019. I installed the same because that was what was available at the time (community version for me, I think the same for my school).
I had a couple of issues with VS2019 so I uninstalled everything and installed 2022 version instead. I then began to use this for the last 2 weeks but when I tried to open my old files, I couldn't.
I did install framework 3.1 again and the code will enter runtime successfully, but I still can't see the code that I wrote. I don't want to re-install VS2019 because it kept on giving me issues with intellisense which I just couldn't fix.
Is there any way I will be able to open my old 2019 files in 2022? Also, will 2019 be able to open 2022 files?
The generic answer to this is mostly yes but maybe no depending on your specifics. That's not a helpful sentence, so let me explain.
For the most part, Visual Studio solutions and projects are cross-compatible1. This means that if you have a project from one version, you can usually open it in another version without issue. The major caveat to this is the range of frameworks supported by each VS version may be different. VS will often be able to open the project, but might not be able to build and run it.
(Because you tagged this with vb.net, I'm limiting this to .NET versions. The same concepts may apply for other platforms.)
For example, VS2019 supports:
.NET version 5 (Visual Studio 16.8 or later)
.NET Framework versions 4.8, 4.7.2, 4.7.1, 4.7, 4.6.2, 4.6.1, 4.6, 4.5.2, 4.5.1, 4.5, and 4.0
.NET Core 3.1, 3.0, 2.2, 2.1, and 1.1.
And VS2022 supports:
.NET Framework versions 4.8, 4.7.2, 4.7.1, 4.7, and 4.6.2
.NET Core 6.0 Preview, 5.0, 3.1, 3.0, 2.2, and 2.1.
Note how VS2022:
DOES NOT support .NET Framework versions 4.0-4.6.1, or .NET Core 1.1
DOES support .NET (Core) 6.0 - which VS2019 does not
It is reasonable to expect that the next version of VS will stop supporting some versions while it adds support for new ones again, so this compatibility range will change with each VS release.
1: Each different type of project requires a Project System to support it. Occasionally, these may be dropped out of support like with the frameworks described above, but with the more severe consequence that VS will not be able to open the project at all. Some examples over time: Silverlight and Windows Phone projects, Setup projects, DNX (early .NET Core) projects, etc.
I'm not cleared in the specification of .NET Framework 4.0. As per my knowledge .net framework 3.0 required .net framework 2.0 and .net framework 3.5 required .net framework 3.0, so I'm not cleared that whether .net framework 4.0 required .net framework 3.5? Whether .net framework 4.0 is standalone or not? I had searched most of the Microsoft helpful sites, but not got anything on that topic. Guys, If you know anything please share.
No, every version of .NET has been standalone. You can install .NET 3.0 with no other version installed, ditto .NET 3.5, ditto 4.0, ditto 4.5 etc.
Now there have been fewer versions of the CLR than there have of the .NET framework overall, but that's a different matter - and doesn't change whether or not you can install .NET without installing anything else.
Likewise some versions of .NET effectively install over the top of others (installing .NET 4.5 when you've got .NET 4.0 installed replaces the .NET 4.0 libraries) but you can still install each version without installing anything else first.
According to MSDN documentation,
public static Assembly LoadFrom(string assemblyFile)
throws BadImageFormatException if
assemblyFile is not a valid assembly.
-or-
Version 2.0 or later of the common language runtime is currently loaded
and assemblyFile was compiled with a later version.
Actually, there is one extra case - loading assembly that is built for x86 from assembly that runs in x64 mode. Maybe it is included in "not a valid assembly" statement, I don't know. But this is reasonable cause of exception.
Ok, but in .NET 4.5 it doesn't! I have a .NET 4.5 WPF app, that loads different appliations for some reason. It is building for Any CPU and I'm starting it on x64 Win 7. I've been testing it on one executable, that is built for .NET 4.0 x86, and it worked fine. But when I switched my app to .NET 4.0 it began to crash on Assembly.Load method!
So, my question is, am I missing something? If not, then how did they do that - loading x86 assembly from x64 process in .NET 4.5? I'm lacking some understanding at this point.
Update
Thanks to Hans Passant, I've figured out my mistake. Actually the behavior of Assembly.Load is no different. It turned out, I didn't notice Prefer 32-bit option in project settings (or Prefer32Bit tag in .csproj file). That's why my process in .NET 4.5 ran in a 32-bit mode. This setting was true when I created WPF .NET 4.5 project. Then, when I swithced to .NET 4.0 it became inactive because there was no such an option in .NET 4.0. And when I switched back to .NET 4.5 it became false, which is so, I guess, for compatibility purpose.
Let's clear one assumption off the table quickly, there is no possible way to have different behavior on a machine that has .NET 4.5 installed. Targeting 4.0 makes no difference at runtime. The only thing that does is select a different set of reference assemblies, they prevent you from accidentally using a class that's available on .NET 4.5 but not on .NET 4.0.
There is no way to have both 4.0 and 4.5 installed on the same machine. .NET 4.5 is not a side-by-side version of the .NET framework, like 3.5 and 4.0 are side-by-side. Installing 4.5 replaces an installed 4.0 version. The CLR, the jitter, all the runtime assemblies plus the C# compiler.
It is best here to focus on the Platform target setting of your EXE project, that's the one that selects the bitness of the process. The kind of mistakes you can make is forgetting that the setting can be different for the Debug vs the Release build. And assuming that the "Active solution platform" combobox in Build + Configuration Manager has any effect. It doesn't, only the Project + Properties, Build tab, Platform target setting matters. This is a very awkward trap that many programmers have fallen into.
I've got an old Windows 2003 server running IIS 6, and I chose .net 4.5 for my latest web app. Problem is I can't get it to run on the server...
.NET 4.0 framework is installed. I've run aspnet_regiis and deployed the website. I gave it it's own application pool. But I'm getting the following error:
The 'targetFramework' attribute in the <compilation> element of the Web.config
file is used only to target version 4.0 and later of the .NET Framework (for
example, '<compilation targetFramework="4.0">'). The 'targetFramework' attribute
currently references a version that is later than the installed version of the
.NET Framework. Specify a valid target version of the .NET Framework, or install
the required version of the .NET Framework.
I saw the requirements for .NET 4.5 as requiring Windows Server 2008 or later, but I'm seeing lots of posts with people just needing to configure the routing for MVC4 so it seems like this should be possible.
So any ideas what I need to do in order for this to work?
EDIT: The strange thing is we are using an ASP.NET Web API site that works just fine... but that should require .net 4.5...
.Net 4.5 cannot be installed on Windows Server 2003.
Instead, you should use MVC 4.0 on .Net 4.0, which will work fine.
We have a large & complex system running under .Net 4.0. We want to start introducing code written for .Net 4.5, but can't (yet) assume that .Net 4.5 is installed on all the developer machines, build machines and test labs. So I'm looking for a way to compile certain projects in MSBuild using assemblies which are available on disk, on machines which have only .Net 4.0 installed.
Per the documentation it seems possible. The 4.5 reference assemblies are available in the msbuild environment, and I've been experimenting with the TargetFrameworkVersion, FrameworkPathOverride and TargetFrameworkMoniker attributes, but so far without success.
Any hints, suggestions or working samples would be most helpful.
To build a .NET Framework 4.5 application, you must also have the .NET Framework 4.5 reference assemblies.
Installation
The .NET Framework 4.5 replaces the common language runtime (CLR), targets, tasks, and tools of the .NET Framework 4 without renaming them. Essentially, it creates a modified and improved .NET Framework 4.