NHibernate 一对多映射和保存

Question

public class Product : EntityBase<Product, int>, IAggregateRoot
{
    public virtual string ProductName { get; set; }
    public virtual List<ProductDetail> Description { get; set; }
}

public class ProductDetail : EntityBase<ProductDetail, int>, IAggregateRoot
{
    public virtual string Description { get; set; }
    public virtual Product Product { get; set; }
}

上述产品实体有多个产品详细信息。我的映射如下；

public class ProductMap : ClassMapping<Product>
{
    public ProductMap()
    {
        Lazy(false);
        Table("Product");

        Id(x => x.ID, map => { map.Column("ID"); map.Generator(Generators.Native); });
        Property(x => x.ProductName, map => map.NotNullable(true));

        Bag(x => x.Description, m => {
            m.Inverse(true); // Is collection inverse?
            m.Cascade(Cascade.All); //set cascade strategy
            m.Key(k => k.Column(col => col.Name("ProductID"))); //foreign key in Detail table
        }, a => a.OneToMany());
    }
}

public class ProductDetailMap : ClassMapping<ProductDetail>
{
    public ProductDetailMap()
    {
        Lazy(false);
        Table("ProductDetail");

        Id(x => x.ID, map => { map.Column("ID"); map.Generator(Generators.Native); });
        Property(x => x.Description, map => map.NotNullable(false));

        ManyToOne(x => x.Product, x =>
        {
            x.Column("ProductID");
        });
    }
}

当我保存这个时；我遇到错误。

An exception of type 'NHibernate.PropertyAccessException' occurred in NHibernate.dll but was not handled in user code Additional information: Invalid Cast (check your mapping for property type mismatches);

Answer 1

对于映射集合，我们必须使用接口(IList<>)

public class Product : EntityBase<Product, int>, IAggregateRoot
{
    public virtual string ProductName { get; set; }
  //public virtual List<ProductDetail>  Description { get; set; }
    public virtual IList<ProductDetail> Description { get; set; }
}

NHibernate 将注入它的 自己的 IList<> 实现 - 这不是 List 的子级...这是 [=18= 所需要的]代理...延迟加载

NHibernate 一对多映射和保存

NHibernate One to Many Mapping and Saving

c#

nhibernate

nhibernate-mapping