Question

在有实体框架的ASP NET MVC 3中,我有一个领域,有导航财产指另一个物体:

public class Person
{
    public String Name {get;set;}

    public Guid CompanyID{get;set;}

    [ForeignKey(CompanyID)]
    public virtual CompanyType Company{ get; set; }
}

When I create an instance of Person and try to add it to the database, the DBContext keeps a cache of this entity Person and sends it to the database. So later on in the lifetime of the same context instance, when I try to access this entity, the Company field is always null since the navigation property never got updated.

是否有办法更新数据库中有哪些内容?

La的负荷工作已经停止。

Answer 1

如果电荷的装载被转用,而且你想要将导航财产装上电荷,你必须代之以新的<代码>Person/code>,而不是用<代码>new即刻发出:

using (var context = new MyDbContext())
{
    var person = context.People.Create(); // creates a lazy loading proxy
    person.CompanyID = 123;
    context.People.Add(person);
    context.SaveChanges();

    var company = person.Company; // lazy loading query happens here
}

如果不装齐,你就可使用明确载荷:

using (var context = new MyDbContext())
{
    var person = new Person();
    person.CompanyID = 123;
    context.People.Add(person);
    context.SaveChanges();

    context.Entry(person).Reference(p => p.Company).Load(); // explicit loading

    var company = person.Company; // no query anymore, Company is already loaded
}

友情链接