Question

我在我的Products类上创建一对多关系到ProductSpecification类时遇到问题，该类有两个主键ProductId，SpecificationId。产品类并不总是有一个ProductSpecification类没有人没有如何解决我的问题我得到一个错误与上限1.我是EF的新手，并先做代码，所以如果你知道该怎么做请请留下详细解释谢谢。

类：

public class ProductSpecification
{      
    [Key]
    [Column(Order = 1)]
    public long ProductId { get; set; }

    [Key]
    [Column(Order = 2)]
    public long SpecificationId { get; set; }


    [ForeignKey("ProductId")]
    public virtual Product Product { get; set; }
    [ForeignKey("SpecificationId")]
    public virtual Specification Specification { get; set; }
}


public class Specification
{
    [Key]
    public long SpecificationId { get; set; }

    [Required(ErrorMessage = "Please enter a product specification name.")]
    [DataType(DataType.Text)]
    public string Name { get; set; }

    [Required(ErrorMessage = "Please enter a product specification value.")]
    [DataType(DataType.Text)]
    public string Value { get; set; }

    [ForeignKey("SpecificationId")]
    public virtual ICollection<ProductSpecification> ProductSpecs { get; set; }
}

的DataContext：

modelBuilder.Entity<ProductSpecification>().HasKey(x => new { x.ProductId, x.SpecificationId });

modelBuilder.Entity<Specification>().HasOptional(x => x.ProductSpecs)
    .WithMany().HasForeignKey(x => x.SpecificationId);

Answer 1

使您的ForeignKey可以为空：

公众长吗？ SpecificationId {get;组; }

公共虚拟规范？规范{get;组; }

EF多个键列一对多

1 个答案: