在ASP.NET Core 2.1中將Value Object作為無效對象

Question

我一直在asp.net core 2.0項目中使用value對象，該項目已在該項目上正常運行。

我將項目更新為2.1，它給我一個錯誤

Invalid object name 'EntityAdress'.

實體：

public class Company : AuditableEntity<long>
{
    public int SalesRepId { get; set; }
    public string Name { get; set; }
    public int StatusId { get; set; }
    public EntityAdress Addresses { get; set; }
    public string BillingAddress { get; set; }
}

public class EntityAdress : ValueObject
{
    private EntityAdress() { }
    public string Address { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public int Zip { get; set; }

    protected override IEnumerable<object> GetAtomicValues()
    {
        yield return Address;
        yield return City;
        yield return State;
        yield return Zip;
    }
}

ValueObject的實現與eshopContainer值對象示例的鏈接完全相同

我正在用於包含DbContext的項目的DbContext

<Project Sdk="Microsoft.NET.Sdk">


  <PropertyGroup>
    <TargetFramework>netcoreapp2.1</TargetFramework>
    <RuntimeFrameworkVersion>2.1.6</RuntimeFrameworkVersion>
  </PropertyGroup>


  <ItemGroup>
    <PackageReference Include="IdentityServer4.AspNetIdentity" Version="1.0.1" />
    <PackageReference Include="IdentityServer4.EntityFramework" Version="2.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="2.1.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="2.1.0" />
    <PackageReference Include="Microsoft.Extensions.Logging" Version="2.1.0" />
    <PackageReference Include="Microsoft.Extensions.Configuration.FileExtensions" Version="2.1.0" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="2.1.0" />
  </ItemGroup>
</Project>

語境：

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.RemovePluralizingTableNameConvention();
    modelBuilder.OnDeleteCascading();

    modelBuilder.ApplyConfiguration(new CompanyEntityTypeConfiguraton());

    base.OnModelCreating(modelBuilder);

}

CompanyEntityTypeConfiguraton：

public class CompanyEntityTypeConfiguraton : IEntityTypeConfiguration<Company>
{
    public void Configure(EntityTypeBuilder<Company> orderConfiguration)
    {
        orderConfiguration.OwnsOne(p => p.Addresses, cb =>
        {
            cb.Property(p => p.City).HasColumnName("City");
            cb.Property(p => p.Address).HasColumnName("Address");
            cb.Property(p => p.State).HasColumnName("State");
            cb.Property(p => p.Zip).HasColumnName("Zip");
        });

    }
}

OnDeleteCascading和RemovePluralizingTableNameConvention：

public static class ModelBuilderExtensions
{
    public static void RemovePluralizingTableNameConvention(this ModelBuilder modelBuilder)
    {
        foreach (IMutableEntityType entity in modelBuilder.Model.GetEntityTypes())
        {
            entity.Relational().TableName = entity.DisplayName();
        }
    }
    public static void OnDeleteCascading(this ModelBuilder modelBuilder)
    {
        foreach (var relationship in modelBuilder.Model.GetEntityTypes().SelectMany(e => e.GetForeignKeys()))
        {
            relationship.DeleteBehavior = DeleteBehavior.Restrict;
        }
    }

}

問題的原因可能是什么？ 實體框架版本是否有問題或實現方面缺少某些內容？

Answer 1

EF Core版本之間的實現始終會有一些更改。 有些可能是錯誤修復，可能導致舊代碼以不同的方式運行。

問題是此代碼：

public static void RemovePluralizingTableNameConvention(this ModelBuilder modelBuilder)
{
    foreach (IMutableEntityType entity in modelBuilder.Model.GetEntityTypes())
    {
        entity.Relational().TableName = entity.DisplayName();
    }
}

首先，您應該排除擁有的類型（記住擁有的類型在EF Core中仍然是實體，因此包含在GetEntityTypes() ）：

modelBuilder.Model.GetEntityTypes().Where(t => !t.IsOwned())

否則，您將更改EF Core的默認行為，即不為所擁有實體創建單獨的表（所謂的表拆分）以實際創建單獨的表，因此，當EF Core構建連接到該表的表的SQL查詢時，會遇到異常不存在。

其次，您應該在所有流利的配置之后調用該代碼，因為在開始OwnsOne沒有這樣標識所擁有的實體（如果未用[Owned]屬性標記的話）-僅在OwnsOne調用之后才發生。

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.ApplyConfiguration(new CompanyEntityTypeConfiguraton());

    base.OnModelCreating(modelBuilder);

    modelBuilder.RemovePluralizingTableNameConvention();
    modelBuilder.OnDeleteCascading();
}