Allow developers to add their custom conventional mapping logic or customize existing logic when they call the ConfigureByConvention method.

Example:

builder.Entity<Customer>(b =>
{
    b.ToTable("Customers"); 

    b.ConfigureByConvention(); // Auto configure by conventions

    b.Property(x => x.Name).IsRequired().HasMaxLength(128);
    b.Property(x => x.EmailAddress).IsRequired(false).HasMaxLength(256);
});

When we configure our entity like that, the b.ConfigureByConvention() method configures ABP's base properties, like SoftDelete, CreationTime, TenantId, ...

See the AbpEntityTypeBuilderExtensions class for all.

To add your own convention, add a new item to the static AbpEntityTypeBuilderExtensions.ConventionalConfigurers list. Example:

AbpEntityTypeBuilderExtensions.ConventionalConfigurers
    .Add(new NamedEntityConfigurer("MyEmailAddressConfigurer", entity =>
    {
        if (entity.Metadata.ClrType.IsAssignableTo<IHasEmailAddress>())
        {
            entity
                .Property("EmailAddress")
                .HasMaxLength(256);
        }
    }));

This example checks if the entity implements IHasEmailAddress (which defines the EmailAddress property), then it sets max length for that property.

You should write this configuration before you first use the DbContext object, typically in the PreConfigureServices method of your module class, or in the Program.cs, before you initialize your application.

You can also remove or replace ABP's default configurers using the AbpEntityTypeBuilderExtensions.ConventionalConfigurers list.