Refactoring the OnConfiguring() method

If we recap on how we have configured the database context, the auto-generated code had a hardcoded connection string used for configuration. To avoid it, we should have a mechanism to pass on the database context options to the DbContext base class; let's see how to do it:

    public partial class MasteringEFCoreDbFirstContext : DbContext
    {
      public virtual DbSet<Blog> Blog { get; set; }
      public virtual DbSet<Post> Post { get; set; }
      protected override void OnConfiguring(DbContextOptionsBuilder
       optionsBuilder)
 {
        // Move this connection string to config file later
        optionsBuilder.UseSqlServer(@"Server=        
        (localdb)\mssqllocaldb;Database=MasteringEFCoreDbFirst;
        Trusted_Connection=True;");
 }
    }

Also include a constructor for the MasteringEFCoreDbFirstContext class, which will initialize the DbContext through dependency injection from the Startup class:

    public 
       MasteringEFCoreDbFirstContext(
        DbContextOptions<MasteringEFCoreDbFirstContext> options)        
      : base(options)
      {
      }

We have seen how to pass on the options to the database context base class, now we will see how the options were configured with a connection string.