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Just installed "ASP.net and web development" - and started with the tutorial "RazorPagesMovie" - step 2. On adding "New Scaffolded Item" I get "Error - There was an error running the selected code generator: 'Package restore failed. Rolling Back package changes for "RazorPagesMovie" Beating on the internet I found
Basically I believe have to install a variety of packages
Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.9"
Include="Microsoft.VisualStudio.Web.CodeGeneration.Core" Version="3.1.
going into Project / Manages NuGet Packages - I do not see them - where do I find these packages and how do I install them (if they are already installed - it creates an even bigger problem)
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@Barry Pocock Hi, about your issue "where do I find these packages and how do I install them" --> When we open the project via Visual Studio, we can double click the project name to see all the nuget packages we installed. The file we open by double clicking the project name is the csproj file which containing project info. In your scenario, I'm afraid you just installed web app developing kit provided by VS installation tool. The next is making sure you already installed the required .net SDK version, just like what AgaveJoe said, .Net 8 is the latest longtimesupport version, and according to the link and package version, it looks like you are trying in a old version SDK. Anyway, you can create a new .net 8 web app, then copy and paste the Package references I shared below into your csproj file if you still faced the same error following the tutorial.
<PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="8.0.2">
<PrivateAssets>all</PrivateAssets>
<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
</PackageReference>
<PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="8.0.1" />
Please write your development environment.
I added Microsoft.EntityFrameworkCore.Tools and Microsoft.VisualStudio.Web.CodeGeneration.Design to my project.csproj as stipulated by Tang Wang and installed .Net 8.0 SDK. Still didn't work. Using NuGet package manager (installed) I see the packages but - "not available in this source".
NuGet Config files - C:\Users\Barry\AppData\Roaming\NuGet.Config and
c:\Program Files (x86)\NuGet\Config\Microsoft.VisualStudio.Offline.config
NuGet Packages Sources (originally nothing) but added Microsoft Visual Studio Offline Packages
NuGet Package Sources Mapping - Nothing
I tried DotNet add - "but no version available"
??
Microsoft Visual Studio Community 2022 - Version 17.9.2
VisualStudio.17.Release/17.9.2+34622.214
Microsoft .NET Framework Version 4.8.09037
Installed Version: Community
ASP.NET and Web Tools 17.9.197.37128
Azure App Service Tools v3.0.0 17.9.197.37128
Azure Functions and Web Jobs Tools 17.9.197.37128
C# Tools 4.9.0-3.24121.1+a98c90d56455379836dd5c845b35fa932b00cfa3
Common Azure Tools 1.10
Microsoft JVM Debugger 1.0
NuGet Package Manager 6.9.1
NuGet Package Manager in Visual Studio. For more information about NuGet, visit https://docs.nuget.org/
Razor (ASP.NET Core) 17.9.2.2412004+684740676513b3b208d5bd5b7f8786dab8d287b7
SQL Server Data Tools 17.9.51.1
TypeScript Tools 17.0.30103.2001
Visual Basic Tools 4.9.0-3.24121.1+a98c90d56455379836dd5c845b35fa932b00cfa3
Visual F# Tools 17.9.0-beta.23614.3+a521e1cd420beb56c15faf6836184fadd2b7937a
Visual Studio IntelliCode 2.2
Ignore this comment
Hi @Barry Pocock ， I have another idea on this issue. Per my understanding, there must be some issue inside the environment but it's hard for us to address it. Therefore, we might have another try by creating a new Asp.net core web application via VS template, and please note, let's choose "Individual Accounts" for Authentication type after selecting the .net version. This will help creating a project along with the database. Then in the new project, you will see an "Area" folder, right click the folder -> choose "Add" -> New scaffolded Item -> choose "Identity" in the left panel of the popup window -> click "Add" button -> choose one of the options in the popup and select the DB context and click "Add". This will help you install all the required packages and environment for Scaffolding. If it doesn't work. I'm afraid we could uninstall VS and reinstall it.
Tiny: Thanks so much for working on this, I especially appreciate your succinct instructions. Unfortunately no luck. Following your instructions -
Then in the new project, you will see an "Area" folder, right click the folder -> choose "Add" -> New scaffolded Item -> choose "Identity" in the left panel of the popup window -> click "Add" button ->"Error running the selected code generator" - so I never got to the add identity.
When I first had the problem (with no immediate solution) I did an uninstall of all items related to .NET. (I had old versions) and then did a reinstall of .NET again with the same result. So I have been down the uninstall and reinstall a couple of times. I just installed it on my sons computer and it worked fine!
Hi Barry, thanks a lot for your kind reply with the details about how you troubleshoot the issue, and just like what you shared, all the steps are correct， but the issue still persist in one of your computers, but others no. So that I'm afraid that there's something wrong within the OS which causing the issue.
The error means there is a mismatch of library versions. The libraries you posted are very old and no longer supported. You should move to a supported version of .NET like .NET 8.
Basically I believe have to install a variety of packages
No, you do not have to install any NuGet packages manually. If you did it, probably the issue is caused by the mismatch of NuGet versions as AgaveJoe mentioned in his answer.
I understand that you followed the following Microsoft tutorial. Please note that the tutorial does not instruct to add any NuGet packages.
Tutorial: Create a Razor Pages web app with ASP.NET Core
If you exactly follow the instruction in the tutorial, the required NuGet packages will be automatically installed in the project at the step of "Scaffold the movie model" in the Part 2.
I suggest you uninstall all the NuGet packages and then try "Scaffold the movie model" in the Part 2 again.
SurferOnWww: Thank you for your input on this. I have not been able locate any facility that would enable me to installed any packages. I did install Visual Studio on another computer, laptop, and it works as advertised. It loaded the correct packages and produced the CRUD web pages, albeit very slowly on a very old laptop. If you read the internet links I initially provided they all say "if it doesn't work - manually install these packages". Other efforts include uninstalling old versions of .NET and uninstalling/reinstalling Visual Studios 2022 on this computer; resulted in the same error. I have yet to find a mechanism to load the appropriate NuGet packages since they do not load automatically. I even did search on the laptop to see it these files were stored locally but could not locate them.