EF Core Configuration Manager Configuration

Setup Connection String

For local development, the ASP.NET Core configuration system reads the connection string from the appsettings.json file. So let's add the connection to that file, as shown below.

{
  "ConnectionStrings": {
    "MyConnection": "Data Source=D:\\BookStoreDB.db"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*"
}

To resolve the connection strings from the config file, we need to enable the extension by calling UseConfigurationManager inside the OnConfiguring method of the DbContext type.

public class BookStore : DbContext
{
    public BookStore(DbContextOptions<BookStore> options) : base(options)
    {
    }

    protected override void OnConfiguring(DbContextOptionsBuilder options)
    {
        options
            .UseConfigurationManager()
            .UseSqlite("Name=MyConnection");
    }

    public DbSet<Author> Authors { get; set; }
    public DbSet<Book> Books { get; set; }
}

You can also specify the connection string from the config file when scaffolding a DbContext at design time.

Scaffold-DbContext Name=MyConnection Microsoft.EntityFrameworkCore.Sqlite