Need info on .net core and .net framework

Question

Need info on .net core and .net framework

MM, Sunil 86

Hi Team,

I have a current project which is built on .net framework 4.7 and now i want to convert that projects to .net core.
Could you please guide me which .net framework i need to install to convert my .net framwork 4.7 project to .net core?.

.Net core 3.1 is latest? -- should we use this.?
.Net 5 is latest? .Net 5 is framework + core right?

Regards,
Sunil

P a u l 10,761 Reputation points

2021-12-03T14:57:55.387+00:00

There's a https://versionsof.net website that's handy for keeping track of current/long-term-support versions of .NET(Core)/.NET Framework btw.

4 answers

Your answer

P a u l 10,761 Reputation points

2021-12-03T14:57:55.387+00:00

There's a https://versionsof.net website that's handy for keeping track of current/long-term-support versions of .NET(Core)/.NET Framework btw.

Answer 1

Rijwan Ansari 766 MVP

Hi @MM, Sunil ,

It is obviously a wise decision to migrate into .NET core for several reasons check here, however it is not straight forward.

Regarding your questions:

.NET 6 is the latest version and is only in core. Going forward, after .NET 5, there won't be .NET framework releases. ( .NET framework 4.8 is the last version).
I would suggest choosing .NET 6 because it would easy to upgrade into next upcoming versions, and also there are numerous advantages.

To start, you need to create a new solution into .NET 6 core and rewrite the code, but most of those code can be reused depending on dependencies.
Also check
https://learn.microsoft.com/en-us/dotnet/core/porting/
https://learn.microsoft.com/en-us/dotnet/core/compatibility/fx-core

Rijwan Ansari 766 Reputation points MVP

2022-02-05T14:21:38.19+00:00

Hi @MM, Sunil

You can take advantages of .NET upgrade assistance.

https://github.com/dotnet/upgrade-assistant

Answer 2

Castorix31 90,521

.NET Core != .NET Framework

Last version is 6 (for VS 2022) : Download .NET 6.0

and : Overview of porting from .NET Framework to .NET

MM, Sunil 86 Reputation points

2021-12-03T16:17:23.41+00:00

Thanks for the reply.

Now we are using visual studio 2019 for our project development.
Now which version of .net core(.NET Core 3.1 or .NET 5.0 .NET 6) i need to install to convert my .net framework 4.7 project to the .net core project?
Castorix31 90,521 Reputation points

2021-12-03T16:35:51.46+00:00

.NET Core 5 if VS 2019 : Download .NET 5.0
(it is what I installed on my OS (Windows 10 21H1/VS 2019)

Answer 3

Karen Payne MVP 35,586 Volunteer Moderator

For VS2019 use .NET Core 5 as .NET Core 6 is for VS2022.

In regards to converting from Framework 4.7, there is not a straight conversion as somethings are not available in .NET Core at all or need NuGet packages. For example there is no BindingNavigator, if working with SQL-Server in 4.7 the reference is already included while in .NET Core 5 you need to install a NuGet package. Other things such as Process.Start need different parameters in some cases.

It takes a little time to get the hang of things but once you do it becomes easier.

See also Overview of porting from .NET Framework to .NET

MM, Sunil 86 Reputation points

2021-12-07T13:36:31.477+00:00
Hi Team,

Thanks for the prompt reply.
I have one doubt, Suppose we have 2 .net framework projects.

Class library project(project1) created using .net framework 4.7

Windows application created(Project2) using .net framework 4.7.

And i have referenced project1 dll to the project2 windows application.

Now if i convert the project2 using the https://dotnet.microsoft.com/platform/upgrade-assistant from .net framework to .net core 6.
Will that project2 run without any issue?

Best Regards,
Sunil
AgaveJoe 30,126 Reputation points

2021-12-07T13:47:40.48+00:00

.NET 6 is not compatible with .NET 4.7. This information is openly published in the official documentation.

Migrate from ASP.NET to ASP.NET Core
MM, Sunil 86 Reputation points

2021-12-07T14:39:27.097+00:00

You means - we can not have/use a reference of DLL (project1 class library developed in .net framework 4.7) to the project2(to be converted to .net 6) while converting the project2 from .net framework to .net core?
Bruce (SqlWork.com) 77,686 Reputation points Volunteer Moderator

2021-12-07T16:19:53.207+00:00

that is correct. .net core and net 5/6 can not call dll's written in 4.* framework. this is also true of nuget packages referenced.

you might be able to recompile your 4.7 projects to .netstandard 2.0 so they work with both 4.7 and .net core. again the .netstandrd 2.0 libraries can not reference 4.7 dll's
MM, Sunil 86 Reputation points

2021-12-09T04:51:03.983+00:00
HI Team,

i have below issue after migrating the .net framework 4.7 to .net 6.

senarios

Class library project(project1) created using .net framework 4.7

Windows application created(Project2) using .net framework 4.7. - Converted to .net 6 using https://dotnet.microsoft.com/platform/upgrade-assistant

i have referenced project1 dll to the project2 windows application.

After converting project2 to .net6 below issues found :
a. error NETSDK1149: project1.dll cannot be referenced because it uses built-in support for WinRT, which is no longer supported in .NET 5 and higher. An updated version of the component supporting .NET 5 is needed.

b. warning NETSDK1182: Targeting .NET 6.0 in Visual Studio 2019 is not supported.

c. Could not resolve this reference. Could not locate the assembly "System.Runtime.Remoting". Check to make sure the assembly exists on disk. If this reference is required by your code, you may get compilation errors.

Please help me to resolve these issues.
Bruce (SqlWork.com) 77,686 Reputation points Volunteer Moderator

2021-12-09T15:43:09.92+00:00

That is correct. You should convert the shared class library to .netstandard 2.0 first, so it can be used by both 4.7 and core.

You can also make it a mult-target framework project so it builds a 4.7 dll and .net standard 2.0 dll, if you need to change nuget packages or code to support core. You can use conditional compile for the different code.

Answer 4

Xingyu Zhao-MSFT 5,381

Hi @MM, Sunil ,

a project1.dll cannot be referenced because it uses built-in support for WinRT

As suggested in the this document : Previous versions of .NET Framework and .NET Core had built-in knowledge of WinRT, a Windows-specific technology. To support the portability and efficiency goals of .NET 5, we lifted the WinRT projection support out of the .NET compiler and runtime and moved it into the C#/WinRT toolkit.

b Targeting .NET 6.0 in Visual Studio 2019 is not supported

In order to use .NET6, you need to install Visual Studio 2022.
In this case, you can target .NET5 when using Visual Studio 2019.

c Could not locate the assembly "System.Runtime.Remoting"

Check: .NET Framework technologies unavailable on .NET Core and .NET 5+ - Several technologies available to .NET Framework libraries aren't available for use with .NET 5+ (and .NET Core), such as app domains, remoting, and code access security (CAS). If your libraries rely on one or more of the technologies listed on this page, consider the alternative approaches mentioned.
Take a look at : I need an alternative similar to System.Runtime.Remoting that is supported in .NET 5.0

Hope them could be helpful.

Best Regards,
Xingyu Zhao
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MM, Sunil 86 Reputation points

2021-12-09T10:27:48.097+00:00

hi team,

thanks so much for your reply.
could you please solution for this below error.

error NETSDK1130: Windows.winmd cannot be referenced. Referencing a Windows Metadata component directly when targeting .NET 5 or higher is not supported. For more information

Best Regards,
Sunil
Xingyu Zhao-MSFT 5,381 Reputation points

2021-12-10T01:34:52.09+00:00
Hi @MM, Sunil ,

error NETSDK1130: Windows.winmd cannot be referenced.

You can refer to the suggestion in the document - NETSDK1130: Can't reference a Windows Metadata component directly :

Remove references to the Microsoft.Windows.SDK.Contracts package. Instead, specify the version of the Windows APIs that you want to access via the TargetFramework property of the project. <TargetFramework>net5.0-windows10.0.19041.0</TargetFramework>

Use the C#/WinRT tool chain to generate or customize WinRT APIs and types for .NET 5 and later versions.
MM, Sunil 86 Reputation points

2021-12-10T12:10:01.327+00:00
HI Team,

I am getting below errors while building the converted(.net framework4,7 to .net core 6) project.

Error CS0117 Activator' does not contain a definition for 'GetObject'

Error CS0117 RegistryHive' does not contain a definition for 'DynData'

Error CS0119 'WindowsRuntimeSystemExtensions.GetAwaiter(IAsyncAction)' is a method, which is not valid in the given context

Could you please suggest us for the above errors.

Best Regards,
Sunil
MM, Sunil 86 Reputation points

2021-12-12T13:53:14.153+00:00

Hi team

Could you please help me for above questions.?

Best Regards
Sunil
Xingyu Zhao-MSFT 5,381 Reputation points

2021-12-13T03:11:49.71+00:00

Hi @MM, Sunil ,
I note that some windows-only libraries were used in your project, so you have to find alternatives for these libraries if you want to convert .NET Framework to .NET6 (which is a cross-platform version of .NET).
For example, .NET Remoting isn't supported on .NET 5+ (including .NET 6), For simple communication across processes, consider inter-process communication (IPC) mechanisms as an alternative to remoting, such as the System.IO.Pipes class or the MemoryMappedFile class. For more complex scenarios, the open-source StreamJsonRpc project provides a cross-platform .NET Standard remoting framework that works on top of existing stream or pipe connections.

Both Activator.GetObject method and Registry.DynData field apply only to .NET Framework. The former you need to find the alternative for .NET Remoting. The latter reads the Windows registry base key HKEY_DYN_DATA which is used only on Windows 95, Windows 98 and Windows ME, so you can consider removing 'Registry.DynData'.

Finally, for WindowsRuntimeSystemExtensions.GetAwaiter method, you can take a look at: Call Windows Runtime APIs in desktop apps.
MM, Sunil 86 Reputation points

2021-12-13T09:42:45.44+00:00
Hi Team,

Could you please provide alternate code for below code.(which i am getting error currently.

(Class1)Activator.GetObject(typeof(IClass1), "ipc://server/UpdateServicI_SERVER"); -- error - Activator' does not contain a definition for 'GetObject'

foreach (var appE in Package.GetapListEntriesAsync().GetAwaiter().GetResults()) -- error - Error CS0012 The type 'IAsyncOperation<>' is defined in an assembly that is not referenced. You must add a reference to assembly 'Windows, Version=255.255.255.255, Culture=neutral, PublicKeyToken=null, ContentType=WindowsRuntime'

Best Regards,
Sunil
MM, Sunil 86 Reputation points

2021-12-13T13:18:58.26+00:00

Hi Team,

Could you please provide answer for my above questions.

Best Regards,
Sunil
Xingyu Zhao-MSFT 5,381 Reputation points

2021-12-14T02:12:52.34+00:00

Hi @MM, Sunil ,
You cannot simply use the alternate code for 'Activator.GetObject' method, so try redesigning your .NET remoting.
For the second question, it's not clear what API you used in your original project. Try to install Microsoft.Windows.CsWinRT.

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Need info on .net core and .net framework

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