Last few months I create console applications with .NET framework and C#.
Now I want to create ASP.NET Core MVC projects, but I cannot choose any .NET Core template.
If I click "Console App (.NET Core)" or "ASP.NET Core Web Application" or any other .NET Core template, I can see this error message:
So, the problem occurs if I choose "Core", other templates work fine.
I have already tried to find a solution on Google.
What could be the problem? I reinstalled VS few times but did not help.
.NET Core does not support COM. COM is a Windows-only thing, and everything in Core is cross-platform. You must run on the full framework if you need to utilize a COM library.
That said, Microsoft has recently release a preview NuGet with some Windows compatibility APIs. This may allow you to utilize COM; I haven't tried it. However, the stated purpose of the NuGet is to make it easier to migrate existing .NET Framework applications to .NET Standard/.NET Core, so it's not considered something you would continue to utilize long-term. Rather, the idea is that you would actively work to migrate code that is not compatible to equivalent .NET Standard/.NET Core APIs, and then eventually remove the package entirely. As a result, it's probably not a good idea to go this route, even if it does enable you to use the COM library, simply because you're not likely to be able to stop at some point in the future.
Long and short, just run on the full framework.
Related
Ive build out a service as a console application, it exists across 2 different projects in the solution, both are in .NET framework. I am wanting to add in an api level to this and am wondering if I should continue to use .NET framework for the web application project, or if I can use .NET Core without messing anything up.
It all depends on the APIs you use in your application. If you only use APIs included in .NET Standard then no problem to use them in an application under .NET 6. Otherwise I join Kirk Woll to migrate your code under .NET 6 especially since the unification of the platform. I think it will remain only .NET 6 aka .NET core in the future.
Our client has complained about the count of .dll files in the .NET Core app we made for them. Their dissatisfaction persists even after we explained that this is how .NET Core works.
Now I do understand their position completely, my jaw dropped too when I created the package for the first time:
Note how small the scroll bar is. Most of the library names begin with Microsoft. or System. - those that don't are libraries that I use and installed manually.
So the question is: is there anything I can do about this to make our client happy? Aren't the System.* libraries already installed on their machine as a part of .NET Core runtime?
We're targeting .NET Core 1.0 at this moment.
You can create two types of deployments for .NET Core applications:
Framework-dependent deployment
Self-contained deployment
It seems you need Framework-dependent deployments (FDD).
Portable (FDD) application is similar to the traditional .NET Framework application. In this case, a certain version of the .NET Core Framework (also known as shared framework, .NET Core Runtime, redist) should be on the target computer, and when the host starts, the process will load Core CLR, Core FX from the frame folder.
Artifacts of the same Portable Application for different versions of the .NET Core platform
You can see what Directory structure of published ASP.NET Core apps should be
To run Portable applications, at least one .NET Core Runtime (shared framework) must be installed on the target machine. The framework files (s) are stored in the C:\Program Files\dotnet\shared folder.
Core is designed to do this. In old .NET Framework apps, there's a runtime dependency on .NET Framework, i.e. the end-user must have the version of the .NET Framework the application targets installed on the machine as well. Core takes a different approach; it brings everything it needs into the build. As a result, you can drop this folder on any machine, no matter how it's set up and "run" it. (Now technically, you need dotnet.exe in order to run it, unless you build as an executable, but that's just to run the main app DLL.)
Anyways, this is by design, and it's actually much better when you think about it. Your app has just the dependencies it actually needs and nothing else. You don't have to worry about external things like what version of .NET Framework is installed, etc.
That said, I know there's some third-party applications (mostly commercial) that can enable you to "bundle" DLLs or even package up everything into a single executable. However, I'm not sure how compatible, if at all, these are with .NET Core. Still, if your client insists, I'd just see if you can find some tool that does that and essentially "hide" the DLLs.
I have a Winforms application developed in c# targetting .Net Framework 4.0. I created a setup for the application and packaged the .Net Framework 4.0 within the setup. During installation, the setup installs the .Net Framework 4.0 (if not installed already), and the application works fine.
I know it's not possible to run .Net application without .Net Framework. Is there some way I can package the CLR, JIT, and all required dll's with my application so that I won't need to install the entire .Net Framework 4.0 on the target machine?
Can i create my own installer for .Net Framework 4.0? Installer which insalls only the libraries which are required for my application, thus eliminating the need to install entire .Net Framework?
I have looked into ngen, Turbo Studio etc. to containerize the application but that does not suit for my purpose. Any help will be highly appreciated.
The .NET Framework was not designed to be deployed partially. I don't think this is possible - even if you will get that to work, it won't be supported officially. You might even see that your app is running but it might crash at any time later as soon as an assembly gets referenced (lazy by reflection, for example) you have no direct reference to.
Having only those parts of the framework deployed which are directly or indirectly referenced by your app is one of the main ideas of .NET Core - but you won't be able to do full-featured UIs with it by now.
Issue
Hi,
I am currently working on implementing a RESTful API in C# using ASP.net Core 2.0 in Visual Studio 2017 (running only via Kestrel, therefore no IIS).
Everything works pretty well, no issues there. The thing is that I now need to integrate and start this REST Server in another project (The REST server being only one of many functionalities that need to be executed at the same time, using a "bootstrap"). My issue here is that the latter project targets .Net Framework 4.5.2 whereas the REST server targets .Net Core 2.0. Thus, when I add the REST server to the references of my bootstrap application, I encounter a couple of errors saying that some of the Nuget packages target the wrong framework.
Solutions I tried
I searched over Google but most of the issues I found were people trying to do the other way round, i.e. adding a .Net Framework-targeted project in a .Net Core application.
The way I understood this .Net implementation support table, is that a .Net standard 2.0 project can support a .Net Core 2.0 project (I am probably wrong).
I tried a couple of things to make it work (which, spoiler alert, obviously and unfortunately did not work as I wouldn't be asking your help) :
Made the boostrap application target .Net Standard 2.0
Made the boostrap application target .Net Framework 4.6.1
Made the REST server application target .Net Standard 2.0 (which it of course didn't work, but I was kind of desperate..)
I made these target change by modifying the .csproj files.
I don't have the exact error codes because I reverted my changes a while back but they all were about projects not targeting the same framework.
So, in a tl;dr manner, what I am asking is :
Is there a way to add a .net Core 2.0 REST server inside a .Net Framework 4.5.2 (or 4.6.1 and higher/ or .Net Standard 2.0) project to start the server inside the application ?
Apologies for any english mistake as it is not my native language.
Don't hesitate to ask more info on my problem if I wasn't clear enough and thanks for the help !
I just can't understand why I can't use an old library in a .net Core app targeting Windows and the full .net framework (I don't care about multi-platform).
Just trying to understand the limits here. I don't want to hit a wall after investing too much into it.
Steps followed:
Create a new .Net core web Application
Added PetaPoco from NuGet (just an example)
Can't use the library
From a comment from you on a deleted answer to this question
It's not about this particular reference. I just want to understand why I can't use an arbitrary Windows DLL. (I don't care about multi-platform) – Eduardo Molteni
It appears you are not too concerned why this specific project is not working (the deleted answer you commented on covered that quite well and if it was not deleted I would have up-voted it) but why in general you can't use a .NET Framework DLL in a .NET Core project.
Here is a diagram showing the layout of the ".NET ecosystem"
Things built for .NET Framework can't use DLLs built specifically for .NET Core, and things built for .NET Core can't use DLLs built specifically for .NET Framework because they are two "siblings" in the hierarchy.
Both .NET Framework and .NET Core can use .NET Standard libraries in their projects because .NET Standard is the "parent" of both the framework and core. Many newer NuGet packages now release versions that target .NET Standard so the library can be used with both versions. See the below chart to see what version of the .NET Standard library is compatible with various platforms. netstandard libraries are forward compatible so something that is compatible with 1.5 (like .NET 4.6.2) is also compatible with versions 1.0-1.4