首先,这不可能是多用户问题,因为我正在本地开发版本的数据库上工作。
当我执行db.SubmitChanges()时,会出现不太具说明性的“未找到或更改行”的错误。如果在SubmitChanges()发生之前刚好中断执行,我可以在SQL Server Management Studio中检查到该行确实存在!
以下是整个函数的代码,以供任何想要帮助的人放入上下文,但问题行在最后(第48行)。
更新 这真的很奇怪:更新matchingTrans.Url(请参见代码的倒数第二行)会导致错误。即使匹配的matchingTrans.Title仍然被更新,注释掉这一行也不会引发错误。
private static void MenuItemUpdate(int languageId, NavigationItem item)
{
using (var db = DataContextFactory.Create<MyDataContext>())
{
// Select existing menu item from database.
var dbItem =
(from i in db.MenuItems
where i.Id == item.Id
select i).Single();
// Obtain ID of link type.
dbItem.FkLinkTypeId = GetLinkTypeByName(
Enum.GetName(typeof (NavigationItemLinkType), item.LinkType)).Id;
// Update the Link field with what is given.
dbItem.Link = item.Link;
db.SubmitChanges();
// Item already exists and needs editing.
// Get associated translations.
var trans =
from t in db.MenuItemTranslations
where t.FkMenuItemId == item.Id
select t;
// If translation exists for given language, edit it.
var matchingTrans =
(from t in trans
where t.FkLanguageId == languageId
select t).SingleOrDefault();
if (matchingTrans == null)
{
// No matching translation - add one.
var newDbTrans = new MenuItemTranslation
{
FkMenuItemId = item.Id,
FkLanguageId = languageId,
Title = item.Title,
Url = item.FriendlyUrl
};
db.MenuItemTranslations.InsertOnSubmit(newDbTrans);
db.SubmitChanges();
}
else
{
// Matching translation - edit it.
matchingTrans.Title = item.Title;
matchingTrans.Url = item.FriendlyUrl;
db.SubmitChanges();
// WTF ERROR: Row not found or changed.
}
}
}