Question

使用的软件：

Visual Studio 2008专业人员服务包1 Sql Server 2005标准版（9.00.4266.00） Windows XP SP3

我有这3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并拖放这三个表

现在只需将该代码放在网页代码隐藏

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

并运行它

您将收到无效投射错误

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

有没有办法在不删除表之间的链接的情况下进行插入？

Answer 1

我实际上就像你指定的那样创建了你的数据库，并在我的盒子上本地运行了这个代码。当我用这行代替真正的GUID时，我没有得到这样的错误：

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

您确定您的GUID格式正确吗？您确定您的表格是否与您指定的完全相同？仔细检查一下......我的猜测是，如果你从头开始重新创建这个示例数据库，你将不会看到这个问题。

Answer 2

我认为直接设置外键ID时Linq2sql不喜欢它。它更喜欢你自己设置外来物。

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

Answer 3

好吧，它实际上是.net 3.5的一个错误，并用.net 4.0修复

但有一个修补程序see detail here

安装该修补程序后，一切都会正常工作

linq2sql在这种特定情况下出现问题

3 个答案: