Question

表Contact通过*→1密钥与表Location有Location ID的关系。以下代码保存除Contact之外的所有Location数据。我做错了什么？ EF 6.0.0.0，MVC 5.2.3.0，但EF 4.4和MVC 4也会导致此错误。

using(MyEntities me = new MyEntities())
{
  Contact ct = me.Contact.SingleOrDefault(x=>x.User.UserID == WebSecurity.CurrentUserId);
  ct.Title = "sometitle"; //assignment and saving works
  ct.Location = me.Location.SingleOrDefault(x=>x.Location_ID == 19); //only assignment works
  me.SaveChanges();
}

由于某些错误，我在从数据库创建EDMX模型时禁止直接使用外键。

更新：Contact和Location都与User UserID有关。这可能是问题的根源吗？

Answer 1

您必须指定位置级别必须包含在最后要保存的上下文中。

所以只需在代码中添加.Include（＆＃34; Location＆＃34;）

using(MyEntities me = new MyEntities())
{
    Contact ct = me.Contact.Include("Location").SingleOrDefault(x=>x.User.UserID == WebSecurity.CurrentUserId);
    ct.Titile = "sometitle"; //assignment and saving works
    ct.Location = me.Location.SingleOrDefault(x=>x.Location_ID == 19); //only assignment works
    me.SaveChanges();
}

EF不会保存外国数据

1 个答案: