OnModelCreating 实体框架核心

Question

此代码在MVC 中，我需要在ASP.net Core 中执行类似的操作，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);
        }

我尝试在Entity Framework Core中使用时出现一些错误：

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?)

Answer 1

在支持 ModelBuilder.Configurations 之前，我使用扩展方法模拟旧的 Entity Framework 构造：

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;
}

然后像这样从 OnModelCreating 调用它...

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

这有点笨拙，但我认为比尝试在主 DbContext 中配置数十个实体更干净。