Backward .NET compatibility for NuGet packages? - c#

I'm accustomed to the Java world: it's generally safe to run an application on a newer JRE that has dependent .jars compiled with older versions of Java.
.Net is a bit stricter. For example, if I build an ASP.NET app with TargetFramework "netcoreapp3.1", then I MUST install ASP.Net Core 3.1 runtime on every host server I deploy the app on. I can't just install .NET 7 on the host server, and expect it to work. Correct?
Q: What about NuGet packages? Do I need to install the corresponding .NET or .NET Core runtimes for every NuGet dependency my app uses?

I would recommend using Docker, or any other container platform like Kubernetes to manage applications like this. It's designed just to avoid situations like this where your application changes to rely on new assets. So you could just basically change the version by just changing a number in your Dockerfile before build and deploy it like any other upgrade. This method is always best practice today. Just swap server application images on your servers for each deployment, no installations.
Alternatively, you could build your application as self-contained (runtime/executable included in your build).
To answer the question, you need the same runtime as your application targers.

Related

Published .Net Core App Warns to Install .Net Core but it's Already Installed

I made a WPF and Console application for someone to use on their private server which I can't have access to. I used Visual Studio 2019's built-in "Publishing Wizard" to create Framework Dependant single-file apps. When the person opened the WPF app they were greeted with the standard warning:
They clicked yes and to my understanding, they installed .Net Core 3.1 which is what the applications target.
After they restarted the computer they got the exact same warning again. I wasn't sure what was going on so I repackaged the apps as self-contained since the installed version of .Net Core was the same as what my applications were targeting.
That seemed to work for a little bit. We ran into some unrelated issues that I had to fix in the code on my end and then I re-published the projects and sent them out.
They tried to use the WPF application and they got the install warning again.
Now no matter what combination of options I pick in the "Publish Wizard" they keep getting the warning.
I'm not sure what to do.
Here's a picture of my publish settings
In my case I had the same issue, and the problem was that I was not deploying the file "MY_PROGRAM_NAME.runtimeconfig.json". After copying this file, which is present in the build output, the application is launched without problems.
Turns out the issue was the fact that the applications were targeting win-x86 and the user only had access to 64-bit runtimes of .Net Core.
For some reason, I thought it would be able to handle a 32-bit version even if it was running 64-bit runtimes.
I guess live and learn.

Running a .NET Core Console Application on Mac or Windows

I've created a .NET Core console application. I want to build the app so that I can execute it on Windows or MacOS without dotnet core being installed on the machine. So I need e.g. for windows an exe.
I've read https://learn.microsoft.com/de-de/dotnet/articles/core/tools/dotnet-publish and I know how to compile the application for the different platform(s).
But no executable gets created. What am I missing here and how do I accomplish my goal?
What you need is to create a self-contained application. The link explains how exactly to modify your project.json to do that.
Also note that while a self-contained application does not have a dependency on .Net Core, it may have other dependencies. Specifically on OSX, I believe you will need to install a specific version of openssl from homebrew.

.NET Core doesn't depend on any installation?

I've been reading about .NET Core and it seems really cool.
There is just one thing that is making me think and I haven't read it anywhere: when I set my asp.net 5 web app to target .NET Core and deploy it, this app doesn't depend AT ALL on the .NET framework installed on the machine that's going to host it?
I mean, the assemblies deployed already contain the CLR, the BCL and the project dependencies? So I can have mutiple web apps hosted in one single machine with different versions of .NET Core, right?
I mean, the assemblies deployed already contain the CLR, the BCL and the project dependencies?
They ship with whichever dependencies are in your project.json file. If you choose to deploy CoreCLR, the runtime will be shipped with your app in order for different apps to be able to run on whichever framework version they consume, side by side. The point is that all of the BCL is slowly packaged into separate NuGet packages which ship with your app, step by step removing the need to deploy the entire BCL.
Some of the other answers cover the BCL dependency aspect but it is important to distinguish that there is the runtime and the BCL (base class library). In the legacy (non dnx) world the lines were often blurred because both the runtime and the bcl were installed together at the system level.
Runtime (dnx) dependency
The dnx provides the launch point for the application. It includes the runtime, Just In Time compiler, bytecode compiler (Roslyn), unmanaged low level libraries, and a small amount of managed code. It is important to keep in mind that the dnx is identified by environment (windows, linux, mac, freebsd, etc), architecture (x86, x64, arm, etc), and runtime (currently coreclr or clr). It is also versioned and this versioning is separate from the bcl version. Newer versions of the dnx may be needed to resolve bugs, improve performance, and add features.
So the host machine will need the appropriate dnx (defined by architecture, environment, runtime, and potentially version in the event of breaking changes). There is more than one way to get the dnx on the host. One option would be to include it with the application (using dnu publish -runtime). Another option would be to use dnvm to install it 'globally'. Either way the runtime is a requirement.
As a side note the dnx for the full runtime (non-core) is only a facade. It is a method of making dnx applications work the same regardless of if they target the full framework or core framework. You may notice the dnx folder for full framework (i.e. dnx-clr-win-x64.1.0.0-beta4) is only about 10MB. If the full framework is not installed then the application will fail at runtime. In essence the dnx for full framework is only a stub which needs the full framework actually installed into GAC as part of system wide install to work.
As my understanding goes deployed bundle can depend on .NET Execution Environment (DNX). But you can publish your bundle in a specific way with --runtime key, so DNX is included too.
If you choose to bundle (publish) the application with a runtime, then the application will use that particular runtime. If you deploy the application without it, then it will use the global runtime (if any) installed on that machine.
Yes, you can have multiple versions of CoreCLR side by side.

Create a standalone exe without the need to install .NET framework

I'm a student and at the moment i'm doing an internship at a company. This internship is about analysing a project. For this project I have made a demo to show to the Marketing director. The demo I have made is a simple project created in Visual Studio 2010 in c# with Windows Forms and a connection to an Access database.
So now i have to show this demo to this director in a presentation but after this presentation the director wants the project on his computer so he can try and use it. The problem is now that the computers here in this company don't have .NET framework 4.0 and the computers are so protected over here that we can't install anything new. To install something you have to go through a procedure that takes weeks.
I have looked al over the internet but all i find is how to install the .NET framework.
Is there any possible way that I can create an standalone exe without the need to install .NET framework? Please help!
If you want to execute an application that is developed using Net Framework 4, you will need to have installed .Net Framework 4 on client computer.
Your application is compiled in CIL (Common Intermediate Language), so it needs to be interpreted by the framework engine.
It is the same if you want to execute a Java program. You will have to install the Java Machine.
The only way you don't need to install frameworks is programming native applications with C, C++.
C# now supports this with .NET Native.
Instead of compiling to intermediate language, it will compile to native code and run with statically linked .NET libraries. Therefore, there will be no .Net Runtime requirements for end-users.
https://msdn.microsoft.com/en-us/vstudio/dn642499.aspx
https://msdn.microsoft.com/en-us/library/dn584397(v=vs.110).aspx
Only works for Windows 10
You can't build a C# executable without .NET Framework. Even if some resources indicate that you can, that only works in theory.
But you could use an older version of .NET Framework like .NET 4.0. If this doesn't work for you, you have to choose a language like C++ which doesn't require CLR at all.
Update 2018:
Do not target .NET 2.0 or 3.5. It's not compatible with the 4.x version. However, .NET 4.0 targeted binaries work with .NET Framework 4.0, 4.5, 4.6, 4.7 and so on. So to reach maximum compatibility, compile with .NET 4.0. You will have to accept that some features will not be available, however, your binary will run virtually anywhere.
(2018: By now, .NET 2.0 - 3.5 has much lower distribution than 4.x)
Delphi is your solution, deploy native bin executables
YES, THIS IS POSSIBLE!
At least 3 ways exist:
1.you can check all OSes that you planning to run your app and build with such version of .NET. As Windows have a built-in framework libs.
Vista -.NET v3.0 -- All service packs
Windows 7 - .NET v3.5 -- All versions and service packs
Windows 8 - .NET v4.0 [Best choice if you are not sure]
Windows 8.1 - .Net v4.5
Windows 10 - .Net v4.6
as they are already pre-installed by default -- no extra install will be needed.
2.For windows 10 you can compile it into native code (but not into CIL) with ".NET Native". This is means that there are no .Net Framework will be needed for apps.
3.There is Turbo Studio (earlier Spoon and earlier XenoCode) that can wrap everything that your app needs and runs it in as a standalone.
From their site:
Turbo Studio
Run .NET Without .NET. Easily embed runtime dependencies such as .NET, Java, and SQL directly into virtual applications. Launch reliably on any desktop, regardless of underlying component installs.
You can use Mono and statically link you program, so your program don't need .NET CLR runtime and act as standalone program.
Mono Project
In more modern versions of .NET such as 5 and 6 and even with releases of .NET Core it had become a supported scenario to produce what is referred to as a single-file executable as well as a self-contained application.
As I understand it, these technologies take place of and build upon some of the capabilities that had been in the Mono development stack for a while now. Typically I've seen this feature used for applications which would be deployed to servers such as web sites and microservices however it could be used for scenarios such as the one that the original poster illustrates.
Using the .NET SDK publishing (producing the executable) for a single-file executable can be done using a command as the one below which comes directly from the documentation.
dotnet publish -r win-x64 -p:PublishSingleFile=true --self-contained true
For more details see Single file deployment and executable in the Microsoft .NET documentation site.
To be honest, it really isnt a problem nowadays. the .NET framework is found on almost every single computer nowadays, and you can even make a installer with Advanced Installer that silently install the .NET framework on your computer when you are installing the programme.

Dotnet 4.0 upgrade from 2.0

i am working on a dotnet C# web application which was initially created with VS 2003. My goal is to upgrade this application to Dotnet 4.0 without changing any functionaltiy. The solution has 9 projects (1 web + 8 Library projects). The Web project refers the 8 libraries in DLLs. To start off, I created a New project in VS2010 and added the all the Project files from the existing source code. Every time i add a project file to my solution, i was prompted with the Converison wizard and i completed the conversion wizard succesfully and now the solution works fine. After the conversion, i noticed that Except the "Web" project, other projects are converted to Dotnet 2.0 but not 4.0. My application runs without error if i run it locally using VS2010. My questions are
Why the Class libaray project did not upgrade to 4.0? Currently the
Web project is shows up as Dotnet 4.0 and Libaray projects shows up
as Dotnet 2.0.
Can i deploy the application to IIS 7.0 with the
Dotnet runtime of 4.0? Will the Dlls created in version 2.0 work if my application
uses Dotnet 4.0 runtime version?
Please help...
If your'e migrating now, why not move directly to Visual Studio 2012, instead of 2010?
Anyway, what you can do is open the project properties in each of your projects, and change the target framework to the .NET framework 4.0.
Then if you get any compilation error you can probably easily solve it individually. This should be relatively easy if your projects are not too big.
As for your specific questions:
The automatic conversion would only change the format of the solution/projects to be compatible with the new version Visual Studio. It shouldn't change the target framework but you can change that yourself.
Yes, assemblies targeting .NET 2.0 can be loaded and used from assemblies targeting .NET 4.0.
1) Upgrading the solution/projects file only upgrades it's format so you can open it in VS 2010. It will usually leave the targeted .NET setting at the previous value. These are two seperate things. The wonderful thing about VS 2010 is it let's you target whatever version of .NET you desire, so no longer do you need multiple version of VS installed to support differnt .NET versions. It didn't change the targetted .NET version because it leaves it up to you. You can change it under the project settings and recompile your library projects to regenerate the DLLs
2) You will need an application pool for .NET 4. .NET is backwards compatible in that a .NET 2.0 app can run on a machine with .net 4 installed. However, the application pool for 2.0 applications must be separate from 4.0 apps. So it's just a matter of putting the app under the right app pool.

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