我通过Nerd Dinner
应用程序工作。在创建操作方法,有下列代码:在插入父对象和子对象之前添加子对象
NerdIdentity nerd = (NerdIdentity)User.Identity;
dinner.HostedById = nerd.Name;
dinner.HostedBy = nerd.FriendlyName;
RSVP rsvp = new RSVP();
rsvp.AttendeeNameId = nerd.Name;
rsvp.AttendeeName = nerd.FriendlyName;
dinner.RSVPs.Add(rsvp);
dinnerRepository.Add(dinner);
dinnerRepository.Save();
我第一次使用Entity Framework 4.1
代码。
这里是我GrantApplication
类:
public class GrantApplication
{
public int Id { get; set; }
// Other properties
public virtual ICollection<AuditEntry> AuditEntries { get; set; }
}
在我的服务层我这样做,一样什么书呆子晚餐做它:
public void Insert(GrantApplication grantApplication)
{
// Add audit entry
grantApplication.AuditEntries.Add(new AuditEntry
{
NewValue = grantApplication.GrantApplicationStateId,
AuditDate = currentDateTime,
EmployeeNumber = submitterEmployeeNumber
});
// Insert the new grant application
grantApplicationRepository.Insert(grantApplication);
}
我AuditEntry类:
public class AuditEntry
{
public int Id { get; set; }
public int OldValue { get; set; }
public int NewValue { get; set; }
public DateTime AuditDate { get; set; }
public string EmployeeNumber { get; set; }
}
我的上下文类别:
public class HbfContext : DbContext
{
public DbSet<Bank> Banks { get; set; }
public DbSet<AccountType> AccountTypes { get; set; }
public DbSet<GrantApplication> GrantApplications { get; set; }
public DbSet<AuditEntry> AuditEntries { get; set; }
protected override void OnModelCreating(DbModelBuilder dbModelBuilder)
{
}
}
我得到一个错误,即grantApplication.AuditEntries为null,因此它无法添加审计入口对象。为什么是我的空,但晚餐。当它试图添加RSVP obkect时,RSVPs不是空的?我将如何解决它?
我需要将AuditEntries添加到HbfContext吗?我的意思是我不会单独使用它。它仅在编辑GrantApplication时使用。
UPDATE
我必须使用书呆子晚餐的旧版本,但是这是我创建的样子:
[HttpPost, Authorize]
public ActionResult Create(Dinner dinner)
{
if (ModelState.IsValid)
{
NerdIdentity nerd = (NerdIdentity)User.Identity;
dinner.HostedById = nerd.Name;
dinner.HostedBy = nerd.FriendlyName;
RSVP rsvp = new RSVP();
rsvp.AttendeeNameId = nerd.Name;
rsvp.AttendeeName = nerd.FriendlyName;
dinner.RSVPs.Add(rsvp);
dinnerRepository.Add(dinner);
dinnerRepository.Save();
return RedirectToAction("Details", new { id=dinner.DinnerID });
}
return View(dinner);
}
这可能是一个较新版本的书呆子晚餐,但我更新了我原来的帖子,以我的。我将会去实例化我的列表。 –