OnModelCreating实体框架核心

这段代码是在MVC，我需要做这样的事情，但在ASP.net Core中，使用Entity Framework Core，或DataAnnotations(我已经将参数从DbModelBuilder(MVC Entity Framework)更改为ModelBuilder(Entity Framework Core))

 protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>(); //error: Conventions is not recognized
            base.OnModelCreating(modelBuilder);
            modelBuilder.Entity<tbl_Line>()
                .HasMany(d => d.tbl_Policy)
                .WithRequired(c => c.tbl_Line) //error WithRequired not recognized
                .HasForeignKey(c => c.int_lineID);
        }

有一些错误，当我试图使用它在Entity Framework Core:

1- 'ModelBuilder' does not contain a definition for 'Conventions' and no extension method 'Conventions' accepting a first argument of type 'ModelBuilder' could be found (are you missing a using directive or an assembly reference?)

2- 'CollectionNavigationBuilder<tbl_Line, tbl_Policy>' does not contain a definition for 'WithRequired' and no extension method 'WithRequired' accepting a first argument of type 'CollectionNavigationBuilder<tbl_Line, tbl_Policy>' could be found (are you missing a using directive or an assembly reference?)

public static EntityTypeBuilder<Project> Map(this EntityTypeBuilder<Project> cfg)
{
    cfg.ToTable("sql_Projects");
    // Primary Key
    cfg.HasKey(p => p.Id);
    cfg.Property(p => p.Id)
        .IsRequired()
        .HasColumnName("ProjectId");
    return cfg;
}

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Project>().Map();
    base.OnModelCreating(modelBuilder);
}