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().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().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://*.com/questions/26957519/ef-core-mapping-entitytypeconfiguration#comment46244976_26957519