c# - EF Composite key fluent API

Question

我正在尝试为实体映射复合键。

public class Customer 
{
    public int CustomerId { get; set; }
    public virtual List<CustomerImage> CustomerImages { get; set; }
}

及其 map :

public class CustomerMap : EntityTypeConfiguration<Customer>
{
    public CustomerMap()
    {
        HasKey(t => t.CustomerId);
        ToTable(DbConstants.k_CustomersImageTable);
    }
}

图像:

public class Image
{
    public int ImageId { get; set; }
}

及其 map :

public class ImageMap : EntityTypeConfiguration<Image>
{
    public ImageMap()
    {
        HasKey(t => t.ImageId);
        ToTable(DbConstants.k_ImagesTable);
    }
}

和导航属性:

public class CustomerImage
{
    public int CustomerId { get; set; }
    public int ImageId { get; set; }
    public virtual Customer CustomerRelated { get; set; }
    public virtual Image ImageRelated { get; set; }
}

及其 map :

public class CustomerImageMap : EntityTypeConfiguration<CustomerImage>
{
    public CustomerImageMap()
    {
        HasKey(t => new { t.CustomerId, t.ImageId });
        Property(t => t.CustomerId).IsRequired().HasColumnOrder(0);
        Property(t => t.ImageId).IsRequired().HasColumnOrder(1);
        HasRequired(t => t.ImageRelated).WithMany().HasForeignKey(x => x.ImageId);
        HasRequired(p => p.CustomerRelated)
            .WithMany(p => p.CustomerImages)
            .WillCascadeOnDelete(false);

        ToTable(DbConstants.k_CustomersImageTable);
    }
}

但我不断收到以下异常:

One or more validation errors were detected during model generation:
System.Data.Entity.Edm.EdmEntityType: : EntityType 'CustomerImage' has no key defined. Define the key for this EntityType.
System.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'CustomerImages' is based on type 'CustomerImage' that has no keys defined.

但是，如果我用数据注释定义复合键，这不是很好，它可以完美地工作:

public class CustomerImage
{
    [Key, Column(Order = 0)]
    public int CustomerId { get; set; }
    [Key, Column(Order = 1)]  
    public int ImageId { get; set; }
}

及其 map :

public class CustomerImageMap : EntityTypeConfiguration<CustomerImage>
{
    public CustomerImageMap()
    {
        ToTable(DbConstants.k_CustomersImageTable);
    }
}

我尝试了多种定义变体，但似乎都不起作用。任何的想法？是 EF 错误吗？

Answer 1

事实证明，我只是忘了将 map 放在 DbContext 上:

modelBuilder.Configurations.Add(new CustomerImageMap());

也就是说，复合 Id 仍然没有以这种方式填充到 $metadata 上。因此，使用数据注释，这是生成的元数据:

<EntityType Name="CustomerImage">
    <Key>
        <PropertyRef Name="CustomerId"/>
        <PropertyRef Name="ImageId"/>
    </Key>
    <Property Name="CustomerId" Type="Edm.Int32" Nullable="false"/>
    <Property Name="ImageId" Type="Edm.Int32" Nullable="false"/>
    <Property Name="LastUpdated" Type="Edm.DateTime"/>
    <NavigationProperty Name="Customer" Relationship="EasyBizy.Entities.Models.EasyBizy_Entities_Models_CustomerImage_Customer_EasyBizy_Entities_Models_Customer_CustomerPartner" ToRole="Customer" FromRole="CustomerPartner"/>
    <NavigationProperty Name="Image" Relationship="EasyBizy.Entities.Models.EasyBizy_Entities_Models_CustomerImage_Image_EasyBizy_Entities_Models_Image_ImagePartner" ToRole="Image" FromRole="ImagePartner"/>
</EntityType>

但是，如果使用 Fluent API 而不是数据注释，则根本不会生成关键部分。为什么？