Fluent API中的快捷方式,可根据需要设置多个属性

Question

1. 这是我目前正在做的事情:

   modelBuilder.Entity().Property(e => e.Name).IsRequired();
   modelBuilder.Entity().Property(e => e.UPC).IsRequired();
   modelBuilder.Entity().Property(e => e.Price).IsRequired();
   modelBuilder.Entity().Property(e => e.Description).IsRequired();

2. 以下是我想做的事情:

   modelBuilder.Entity().属性(e => e.Name).IsRequired().属性(e => e.UPC).IsRequired().属性(e => e.Price).IsRequired().属性( e => e.Description).IsRequired()

但后者不起作用.有没有其他方法不必每次重复modelBuilder.Entity()？

1. 这是目前最精辟的选择:

   var e = modelBuilder.Entity(); e.Property(e => e.Name).IsRequired();
   e.Property(e => e.UPC).IsRequired();
   e.Property(e => e.Price).IsRequired();
   e.Property(e => e.Description).IsRequired();

Answer 1

这与所有现有的DbModelBuilder扩展方法兼容,因为它只是在顶部添加了一个流畅的层,但它确实带来了一些语法开销.不完全是你要求的,但不涉及支持代码.尚未对此进行全面测试,但如果您对语法感到满意,它应该可以正常工作:

// First option - like this better because it has less cruft than multiple Has invocations

var modelBuilder = new DbModelBuilder();
var modelConfiguration = new ModelConfigurator(modelBuilder);

modelConfiguration.Entity<Product>().Has(e => {
                                         e.Property(en => en.Name).IsRequired();
                                         e.Property(en => en.UPC).IsRequired();
                                         e.Property(en => en.Price).IsRequired();
                                         e.Property(en => en.Description).IsRequired();}
                                        );           

要么

var modelBuilder = new DbModelBuilder();
var modelConfiguration = new ModelConfigurator(modelBuilder);
modelConfiguration.Entity<Product>().Has(e => e.Property(en => en.Name).IsRequired())
                                    .Has(e => e.Property(en => en.UPC).IsRequired())
                                    .Has(e => e.Property(en => en.Price).IsRequired())
                                    .Has(e => e.Property(en => en.Description).IsRequired());

// continue configuring properties, and creating methods on ModelConfigurator as needed

支持代码:

  public class Product{
        public string Name {get;set;}
        public double Price {get;set;}
        public string UPC {get;set;}
        public string Description {get;set;}

    }

    public class ModelConfigurator{

        public DbModelBuilder ModelBuilder{get;set;}

        public ModelConfigurator(DbModelBuilder modelBuilder){
            ModelBuilder = modelBuilder;
        }

        public EntityConfigurator<TEntity> Entity<TEntity>() where TEntity : class {
            var entity = ModelBuilder.Entity<TEntity>();
            return new EntityConfigurator<TEntity>(entity);
        }
    }

    public class EntityConfigurator<TEntity> where TEntity : class{

        public EntityTypeConfiguration<TEntity> EntityTypeConfiguration {get;set;}

        public EntityConfigurator(EntityTypeConfiguration<TEntity> entityTypeConfiguration){
            EntityTypeConfiguration = entityTypeConfiguration;
        }

        public EntityConfigurator<TEntity> Has(Action<EntityTypeConfiguration<TEntity>> a){
            a(this.EntityTypeConfiguration);
            return this;
        }
    }