我有以下课程:
public class Parent
{
public virtual int ParentId { get; set; }
public virtual string Name { get; set; }
public virtual ICollection<Child> Children { get; set; }
}
public class Child
{
public virtual int ChildId { get; set; }
public virtual string Name { get; set; }
//public virtual int ParentId { get; set; }
public virtual Parent Parent { get; set; }
}
这些类以一对多的关系映射到数据库中的相应表。在我的映射类中,我执行以下操作:
using FluentNHibernate.Mapping;
public partial class ParentMap : ClassMap<Parent>
{
public ParentMap()
{
Id(p => p.ParentId).Column.("PARENT_ID").GeneratedBy.Native();
Map(p => p.Name).Column("PARENT_NAME").Not.Nullable();
HasMany<Child>(p => p.Children).Cascade.All().LazyLoad().Inverse().AsSet();
}
}
public partial class ChildMap : ClassMap<Child>
{
public ChildMap()
{
Id(c => c.ChildId).Column("CHILD_ID").GeneratedBy.Native();
Map(c => c.Name).Column("CHILD_NAME").Not.Nullable();
References<Parent>(c => x.Parent).Column("PARENT_ID").Not.LazyLoad().Not.Nullable();
}
}
我需要做的是公开(取消注释上面类定义中的行)Child类中的ParentId属性,以便我可以执行以下操作:
var child = new Child();
child.ParentId = 1;
也就是说,我希望能够通过child.ParentId属性将Parent附加到Child,同时仍然可以通过child.Parent属性访问Parent。例如,
// i currently have to do the following in order to link the child with
// the parent when I update an existing Child instance (ParentService() and
// ChildService() are service classes that sit between my applications and
// NHibernate).
var parentService = new ParentService();
var parent = parentService.GetById(1);
var child = new Child() { ChildId = 2, Parent = parent, Name = "New Name" };
var childService = new ChildService();
childService.Save(child);
// in a different project, i access the Parent object via the child's
// Parent property
var childService = new ChildService();
var child = childService.GetById(2);
Console.WriteLine(child.Parent.Name);
// i want to do this instead
var child = new Child() { Id = 2, ParentId = 1, Name = "New Name" };
var childService = new ChildService();
childService.Save(child);
Console.WriteLine(child.Id); // 11
// [ ... ]
var childService = new ChildService();
var child = childService.GetById(2);
Console.WriteLine(child.Parent.Name);
如何更改映射以实现此目的? TIA,
拉尔夫汤普森
答案 0 :(得分:4)
这不是NHibernate的正确用法。
要获取父使用的ID:
var parentId = child.Parent.Id; //this does not cause loading
要按Id设置父级,请使用
child.Parent = session.Load<Parent>(parentId); //this never goes to the DB either