.net Core EF统一配置实体类型

一般情况需要对某个实体进行一些配置时代码如下:

protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            modelBuilder.Entity<Product>().Property(p => p.Name).HasMaxLength(50).IsRequired();
        }

如果按照上面代码对实体类型进行配置,当实体Entity特别多时难免不便于维护,如果能自动加载执行实体配置的相关类再好不过了

以下代码即可实现统一加载实体配置类并执行

using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using System.Reflection;
using System.Linq;

namespace DAL.Mapping
{
    public interface IEntityMappingConfiguration
    {
        void Map(ModelBuilder b);
    }

    public interface IEntityMappingConfiguration<T> : IEntityMappingConfiguration where T : class
    {
        void Map(EntityTypeBuilder<T> builder);
    }

    public abstract class EntityMappingConfiguration<T> : IEntityMappingConfiguration<T> where T : class
    {
        public abstract void Map(EntityTypeBuilder<T> b);

        public void Map(ModelBuilder b)
        {
            Map(b.Entity<T>());
        }
    }

    public static class ModelBuilderExtenions
    {
        private static IEnumerable<Type> GetMappingTypes(this Assembly assembly, Type mappingInterface)
        {
            return assembly.GetTypes().Where(x => !x.IsAbstract && x.GetInterfaces().Any(y => y.GetTypeInfo().IsGenericType && y.GetGenericTypeDefinition() == mappingInterface));
        }

        public static void AddEntityConfigurationsFromAssembly(this ModelBuilder modelBuilder, Assembly assembly)
        {
            var mappingTypes = assembly.GetMappingTypes(typeof(IEntityMappingConfiguration<>));
            foreach (var config in mappingTypes.Select(Activator.CreateInstance).Cast<IEntityMappingConfiguration>())
            {
                config.Map(modelBuilder);
            }
        }
    }
}

使用:

using Entity.Table;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using System;
using System.Collections.Generic;
using System.Text;

namespace DAL.Mapping
{
    public class ProductConfiguration : EntityMappingConfiguration<Product>
    {
        public override void Map(EntityTypeBuilder<Product> b)
        {
            b.ToTable("Product", "HumanResources")
                .HasKey(p => p.Id);

            b.Property(p => p.Name).HasMaxLength(50).IsRequired();
        }
    }
}

自动加载加载并执行继承了EntityMappingConfiguration的类达到统一对实体类型进行配置的目的

protected override void OnModelCreating(ModelBuilder modelBuilder)
        {            
            base.OnModelCreating(modelBuilder);
            modelBuilder.AddEntityConfigurationsFromAssembly(GetType().Assembly);
        }

 参考:

https://stackoverflow.com/questions/26957519/ef-core-mapping-entitytypeconfiguration#comment46244976_26957519
posted @ 2017-10-12 20:29 Chaunce 阅读(...) 评论(...) 编辑 收藏