This error appears to me. I use .NET 8. The project is divided into three layers. The presentation layer is a web project. The rest of the layers are class libraries. I installed the necessary libraries, all of which are version 8.

Quick action the error in the IDE and it'll give you the option(s) needed to fix this problem.

Also, I would not recommend doing this. In general connection strings and other "static" configuration should be done as part of app startup in your entry point, not here when configuring the context. This method is designed for making any final configuration changes needed before the context is ready to go. Setting connection strings should be done as part of the app startup because they should be stored outside the code. You should probably move this call into where you're calling AddDbContext which is where it normally occurs.

I suggest that you create ASP.NET Core MVC app according to the following tutorial:

Get started with ASP.NET Core MVC

Do not skip Part 1 through Part 4.

At the Scaffold movie pages section of Part 4, add a model to an ASP.NET Core MVC app,

Scaffolding adds the following packages:

• Microsoft.EntityFrameworkCore.SqlServer
• Microsoft.EntityFrameworkCore.Tools
• Microsoft.VisualStudio.Web.CodeGeneration.Design

Scaffolding creates the following:

• A movies controller: Controllers/MoviesController.cs
• Razor view files for Create, Delete, Details, Edit, and Index pages: Views/Movies/*.cshtml
• A database context class: Data/MvcMovieContext.cs

Scaffolding updates the following:

• Inserts required package references in the MvcMovie.csproj project file.
• Registers the database context in the Program.cs file.
• Adds a database connection string to the appsettings.json file.

The automatic creation of these files and file updates is known as scaffolding.