使用外键删除 LINQ 中的记录 - 无效转换异常

发布于 2024-07-09 03:06:55 字数 2519 浏览 5 评论 0原文

我有一个简单的数据库：

ARTICLE
----------
ArticleId (PK),
ArticleTitle
..other stuff...

USER-ARTICLE
------------
ArchiveId (PK),
UserId,
ArticleId
..other stuff...

articleId 是外键。

我希望能够使用以下代码通过 UserArticleId 删除用户文章行，

UserArticle myobjtodelete = PersonalArchiveDb.UserArticles.Single(ua => ua.ArchiveId == 3);
PersonalArchiveDb.UserArticles.DeleteOnSubmit(myobjtodelete);
PersonalArchiveDb.SubmitChanges();

^{（是的，我知道我可以在删除中执行该语句，而不是检索对象，它是用于调试目的，以确保对象确实存在 - 确实存在。）}

当调试器点击 SubmitChanges() 行时，我收到运行时错误：

指定的演员阵容无效。

这是堆栈跟踪，

位于 System.Data.Linq.IdentityManager .StandardIdentityManager .SingleKeyManager`2.TryCreateKeyFromValues(Object[] 值, V& v) at System.Data.Linq.IdentityManager.StandardIdentityManager.IdentityCache`2.Find(对象[] 键值）在 System.Data.Linq.IdentityManager.StandardIdentityManager.Find（元类型类型，Object[] keyValues）位于 System.Data.Linq.CommonDataServices.GetCachedObject（MetaType 类型，对象[] keyValues）位于 System.Data.Linq.ChangeProcessor.GetOtherItem(MetaAssociation assoc, 对象实例）位于 System.Data.Linq.ChangeProcessor.BuildEdgeMaps() 在 System.Data.Linq.ChangeProcessor.SubmitChanges（冲突模式故障模式）在 System.Data.Linq.DataContext.SubmitChanges（冲突模式失败模式）
在 System.Data.Linq.DataContext.SubmitChanges() 处 Driver_SOC_ASO.Controls.PersonalArchive.ArchiveListing.grdArchive_RowDeleting（对象发送者、GridViewDeleteEventArgs e) 中 C:\work\Driver.Net\Driver-SOC-ASO\Driver-SOC-ASO\Controls\PersonalArchive\ArchiveListing.ascx.cs:line 78 于 System.Web.UI.WebControls.GridView.OnRowDeleting（GridViewDeleteEventArgs e) 在 System.Web.UI.WebControls.GridView.HandleDelete(GridViewRow 行，Int32 rowIndex）位于 System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, 布尔值 CausesValidation、字符串验证组）位于 System.Web.UI.WebControls.GridView.RaisePostBackEvent（字符串事件参数) at System.Web.UI.WebControls.GridView.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent（字符串事件参数) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler) 源控件，字符串事件参数）位于 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)
在 System.Web.UI.Page.ProcessRequestMain（布尔值 includeStagesBeforeAsyncPoint、布尔值 includeStagesAfterAsyncPoint)

我不知所措，有什么想法吗？

原文

I have a simple database:

ARTICLE
----------
ArticleId (PK),
ArticleTitle
..other stuff...

USER-ARTICLE
------------
ArchiveId (PK),
UserId,
ArticleId
..other stuff...

The articleId's are foreign keys.

I want to be able to delete a user article row by UserArticleId using the following code,

UserArticle myobjtodelete = PersonalArchiveDb.UserArticles.Single(ua => ua.ArchiveId == 3);
PersonalArchiveDb.UserArticles.DeleteOnSubmit(myobjtodelete);
PersonalArchiveDb.SubmitChanges();

^{(Yes I'm aware I can do the statement inside the delete rather than retrieving the object, it was for debugging purposes to make sure the object definitely exists - it does.)}

When the debugger hits the SubmitChanges() line, I get a runtime error:

Specified cast is not valid.

Here is the stack trace,

at System.Data.Linq.IdentityManager
.StandardIdentityManager
.SingleKeyManager`2.TryCreateKeyFromValues(Object[] values, V& v) at
System.Data.Linq.IdentityManager.StandardIdentityManager.IdentityCache`2.Find(Object[]
keyValues) at
System.Data.Linq.IdentityManager.StandardIdentityManager.Find(MetaType
type, Object[] keyValues) at
System.Data.Linq.CommonDataServices.GetCachedObject(MetaType type,
Object[] keyValues) at
System.Data.Linq.ChangeProcessor.GetOtherItem(MetaAssociation assoc,
Object instance) at
System.Data.Linq.ChangeProcessor.BuildEdgeMaps() at
System.Data.Linq.ChangeProcessor.SubmitChanges(ConflictMode
failureMode) at
System.Data.Linq.DataContext.SubmitChanges(ConflictMode failureMode)
at System.Data.Linq.DataContext.SubmitChanges() at
Driver_SOC_ASO.Controls.PersonalArchive.ArchiveListing.grdArchive_RowDeleting(Object
sender, GridViewDeleteEventArgs e) in
C:\work\Driver.Net\Driver-SOC-ASO\Driver-SOC-ASO\Controls\PersonalArchive\ArchiveListing.ascx.cs:line
78 at
System.Web.UI.WebControls.GridView.OnRowDeleting(GridViewDeleteEventArgs
e) at System.Web.UI.WebControls.GridView.HandleDelete(GridViewRow
row, Int32 rowIndex) at
System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, Boolean
causesValidation, String validationGroup) at
System.Web.UI.WebControls.GridView.RaisePostBackEvent(String
eventArgument) at
System.Web.UI.WebControls.GridView.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String
eventArgument) at
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler
sourceControl, String eventArgument) at
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)
at System.Web.UI.Page.ProcessRequestMain(Boolean
includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)