cant Installer les packages [core .net] en utilisant le code de Visual Studio (dotnet cli)


J'utilisant le dernier cadre de base asp 3.1. Essaie de configurer ma base de données. mais il y a un problème. Je ne peux pas sembler installer les packages suivants

dotnet tool install --global dotnet-ef
dotnet tool install --global dotnet-aspnet-codegenerator
dotnet add package Microsoft.EntityFrameworkCore.SQLite
dotnet add package Microsoft.VisualStudio.Web.CodeGeneration.Design
dotnet add package Microsoft.EntityFrameworkCore.Design
dotnet add package Microsoft.EntityFrameworkCore.SqlServer

i get the following errors. will appreciate it if any one can help with 
a solution.

error NU1100: Unable to resolve 'dotnet-aspnet-codegenerator ' for '.NETCoreApp,Version=v3.1'.
error NU1100: Unable to resolve 'dotnet-aspnet-codegenerator ' for '.NETCoreApp,Version=v3.1/any'.
The tool package could not be restored.
Tool 'dotnet-aspnet-codegenerator' failed to install. This failure may have been caused by:

* You are attempting to install a preview release and did not use the --version option to specify the version.
* A package by this name was found, but it was not a .NET Core tool.
* The required NuGet feed cannot be accessed, perhaps because of an Internet connection problem.
* You mistyped the name of the tool.

Cela se produit lorsque je tente d'installer les packages.

Créé 13/01/2020 à 22:04
source utilisateur
Dans d'autres langues...                            

Cookies help us deliver our services. By using our services, you agree to our use of cookies. Learn more