Apply all IEntityTypeConfiguration derived classes using EF Core 2.0

For EF Core <= 2.1

You can write an extension method as follows:

public static class ModelBuilderExtensions
{
    public static void ApplyAllConfigurations(this ModelBuilder modelBuilder)
    {
        var typesToRegister = Assembly.GetExecutingAssembly().GetTypes().Where(t => t.GetInterfaces()
            .Any(gi => gi.IsGenericType && gi.GetGenericTypeDefinition() == typeof(IEntityTypeConfiguration<>))).ToList();

        foreach (var type in typesToRegister)
        {
            dynamic configurationInstance = Activator.CreateInstance(type);
            modelBuilder.ApplyConfiguration(configurationInstance);
        }
    }
}

Then in the OnModelCreating as follows:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
   base.OnModelCreating(modelBuilder);

   modelBuilder.ApplyAllConfigurations();
}

For EF Core >= 2.2

From EF Core 2.2 you don't need to write any custom extension method. EF Core 2.2 added ApplyConfigurationsFromAssembly extension method for this purpose. You can just use it as follows:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
   base.OnModelCreating(modelBuilder);

   modelBuilder.ApplyConfigurationsFromAssembly(typeof(UserConfiguration).Assembly); // Here UseConfiguration is any IEntityTypeConfiguration
}

Thank you.