Linq to sql 具有此特定结构的linq2sql出现问题

使用的软件：

Visual studio 2008专业版及服务包1
Sql Server 2005标准版（9.00.4266.00） WindowsXPSP3

我有三张桌子：

    GO
    SET ANSI_NULLS ON
    GO
    SET QUOTED_IDENTIFIER ON
    GO
    SET ANSI_PADDING ON
    GO
    CREATE TABLE [dbo].[Table_2](
        [table2id] [int] IDENTITY(1,1) NOT NULL,
        [table2filler] [varchar](max) NULL,
     CONSTRAINT [PK_Table_2] PRIMARY KEY CLUSTERED 
    (
        [table2id] ASC
    )WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
    ) ON [PRIMARY]
    GO
    SET ANSI_PADDING OFF
    GO
    SET ANSI_NULLS ON
    GO
    SET QUOTED_IDENTIFIER ON
    GO
    CREATE TABLE [dbo].[Table_1](
        [table1id] [int] IDENTITY(1,1) NOT NULL,
        [table1guid] [uniqueidentifier] NOT NULL,
     CONSTRAINT [PK_Table_1] PRIMARY KEY CLUSTERED 
    (
        [table1id] ASC
    )WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
    ) ON [PRIMARY]
    GO
    CREATE UNIQUE NONCLUSTERED INDEX [IX_Table_1] ON [dbo].[Table_1] 
    (
        [table1guid] ASC
    )WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
    GO
    SET ANSI_NULLS ON
    GO
    SET QUOTED_IDENTIFIER ON
    GO
    SET ANSI_PADDING ON
    GO
    CREATE TABLE [dbo].[Table_3](
        [tableguid] [uniqueidentifier] NOT NULL,
        [table2id] [int] NOT NULL,
        [table3filler] [varchar](max) NULL,
     CONSTRAINT [PK_Table_3] PRIMARY KEY CLUSTERED 
    (
        [tableguid] ASC,
        [table2id] ASC
    )WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
    ) ON [PRIMARY]
    GO
    SET ANSI_PADDING OFF
    GO
    ALTER TABLE [dbo].[Table_3]  WITH CHECK ADD  CONSTRAINT [FK_Table_3_Table_1] FOREIGN KEY([tableguid])
    REFERENCES [dbo].[Table_1] ([table1guid])
    ON DELETE CASCADE
    GO
    ALTER TABLE [dbo].[Table_3] CHECK CONSTRAINT [FK_Table_3_Table_1]
    GO
    ALTER TABLE [dbo].[Table_3]  WITH CHECK ADD  CONSTRAINT [FK_Table_3_Table_2] FOREIGN KEY([table2id])
    REFERENCES [dbo].[Table_2] ([table2id])
    ON DELETE CASCADE
    GO
    ALTER TABLE [dbo].[Table_3] CHECK CONSTRAINT [FK_Table_3_Table_2]
    GO

    INSERT INTO [dbo].[Table_2]
               ([table2filler])
         VALUES
               ('test')
    print 'table2id:'
    print scope_identity()

    GO

    declare @guid uniqueidentifier
    set @guid=newid()
    print 'table1guid:'
    print @guid

    INSERT INTO [dbo].[Table_1]
           ([table1guid])
     VALUES
           (@guid)

    GO

现在打开一个新的web应用程序项目，创建一个新的dbml并拖放这3个表

现在只需将代码放入网页codebehind中

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    Dim test As New Table_3

    Dim db As New DataClasses1DataContext

    test.table2id = 1
    test.tableguid = New Guid("guid from table 1")
    test.table3filler = "a"

    db.Table_3s.InsertOnSubmit(test)
    db.SubmitChanges()

End Sub

然后运行它

您将得到一个无效的强制转换错误

到目前为止，我能够运行该代码的唯一方法是删除DBML中表之间的链接

---

有没有一种方法可以在不删除表之间链接的情况下进行插入？

我实际上按照您的指定创建了数据库，并在我的框中本地运行了这段代码。当我在这一行中替换实际GUID时，我没有收到这样的错误：

   test.tableguid = New Guid("guid from table 1")

---

你确定你的guid格式正确吗？是否确实创建的表与指定的完全相同？仔细检查一下。。。我的猜测是，如果您从头开始重新创建这个示例db，您将不会看到这个问题

我相信Linq2sql不喜欢直接设置外键id。它希望您设置外部对象本身

test.table_2 = db.Table_2.First(t2 => t2.table2id = 1);
test.tableguid = New Guid("guid from table 1") 
test.table3filler = "a"

---

好的，它实际上是.NET3.5中的一个bug，并用.NET4.0修复

但是有一个修补程序

---

安装修补程序后，一切正常运行

我更新了sql脚本，自动插入新行并返回密钥，但仍然出现无效强制转换错误。对我来说，插入的唯一方法是删除每个表之间的dbml文件中的链接。看我自己的答案，这实际上是一个错误。看我自己的答案，这实际上是一个错误