注册实体映射

Question

我正在 asp.net 核心 项目中使用 EF 核心。我通过覆盖上下文 class 中的 OnModelCreating 函数来映射我的实体。我可以轻松地手动映射这些实体。好吧，我最好 post 我的代码并解释..

这是我在上下文中所做的 class:

protected override void OnModelCreating(ModelBuilder builder)
    {        
        base.OnModelCreating(builder);
        //builder.RegisterEntityMapping<CodeTable, CodeTableMap>();
        builder.RegisterEntityMapping<Country, CountryMap>();
        builder.RegisterEntityMapping<State, StateMap>();
        builder.RegisterEntityMapping<City, CityMap>();
        builder.RegisterEntityMapping<User, UserMap>();
        builder.RegisterEntityMapping<Prospect, ProspectMap>();
    }

Country.cs

public class Country:BaseEntity
{

    public string CountryCode { get; set; }
    public string CountryName { get; set; }
    public string Currency { get; set; }
    public string CurrencyName { get; set; }
    public string UnitOfMeasure { get; set; }
    public string TelephoneCountryCode { get; set; }
    public string CurrencySymbol { get; set; }

    public virtual ICollection<State> States { get; set; }
    public virtual ICollection<City> Cities { get; set; }
}

CountryMap.cs

public class CountryMap : QuantumEntityTypeConfiguration<Core.Domain.Country>
{
    public override void Map(EntityTypeBuilder<Core.Domain.Country> builder)
    {
        builder.ToTable("Country");
        builder.HasKey(pr => pr.CountryCode);

        builder.HasMany(m => m.Cities).WithOne(i=> i.Country).HasForeignKey(m=> m.CountryCode);
        builder.HasMany(m => m.States).WithOne(i => i.Country).HasForeignKey(m => m.CountryCode);
    }
}

但是，我想动态地进行，因为稍后映射所有模型会很忙。我可以在 nopCommerce 的上下文中找到解决方案 class 他们这样做的地方：

 protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        //dynamically load all configuration
        //System.Type configType = typeof(LanguageMap);   //any of your configuration classes here
        //var typesToRegister = Assembly.GetAssembly(configType).GetTypes()

        var typesToRegister = Assembly.GetExecutingAssembly().GetTypes()
        .Where(type => !String.IsNullOrEmpty(type.Namespace))
        .Where(type => type.BaseType != null && type.BaseType.IsGenericType &&
            type.BaseType.GetGenericTypeDefinition() == typeof(NopEntityTypeConfiguration<>));
        foreach (var type in typesToRegister)
        {
            dynamic configurationInstance = Activator.CreateInstance(type);
            modelBuilder.Configurations.Add(configurationInstance);
        }
        //...or do it manually below. For example,
        //modelBuilder.Configurations.Add(new LanguageMap());



        base.OnModelCreating(modelBuilder);
    }

我尝试实现它，但出现错误：

 protected override void OnModelCreating(ModelBuilder builder)
    {
        // TODO: Use Dynamic mapping by getting classes which uses QuantumEntityTypeConfiguration
        var typesToRegister = Assembly.GetExecutingAssembly().GetTypes()
        .Where(type => !String.IsNullOrEmpty(type.Namespace))
        .Where(type => type.BaseType != null && type.BaseType.IsGenericType &&
            type.BaseType.GetGenericTypeDefinition() == typeof(QuantumEntityTypeConfiguration<>));
        foreach (var type in typesToRegister)
        {
            dynamic configurationInstance = Activator.CreateInstance(type);                   
            builder.Configurations.Add(configurationInstance); //Error in this line specifying:ModelBuilder has no defination for Configuration.
        }}

错误

nopCommerce 使用 DbModelBuilder 来自命名空间：System.Data.Entity 我使用 ModelBuilder 在命名空间下：Microsoft.EntityFrameworkCore。

所以，如果您有任何解决方案或建议。请告诉我。

Answer 1

在 EF Core 中，在 ModeBuilder as of now 上没有可用的 Configurations 属性。

解决此问题的一种方法是将您的配置更改为

public class CountryMap : QuantumEntityTypeConfiguration<Country>
{
    public CountryMap(ModelBuilder modelBuilder)
    {
        EntityTypeBuilder<Country> builder = modelBuilder.Entity<Country>()

        builder.ToTable("Country");
        builder.HasKey(pr => pr.CountryCode);

        builder.HasMany(m => m.Cities).WithOne(i=> i.Country).HasForeignKey(m=> m.CountryCode);
        builder.HasMany(m => m.States).WithOne(i => i.Country).HasForeignKey(m => m.CountryCode);
    }
}

然后您可以将它们添加到 DbContext 的 on OnModelCreating 方法中，如下所示：

foreach (var type in typesToRegister)
{       
    Activator.CreateInstance(type, modelBuilder);
}

注册实体映射

Registering Entity Mapping

asp.net-core

entity-framework-core

data-mapping