我收到一个InvalidCastException试图插入一个项目将使用LINQ到SQL数据库时。据我所知,一切都是正确的类型。
I am getting an InvalidCastException when trying to insert an item into a database using LINQ-to-SQL. As far as I can tell, everything is the proper type.
在SQL表(有删节):
The SQL table is (abridged):
CREATE TABLE [dbo].[Timer](
[TimerId] [int] IDENTITY(1,1) NOT NULL,
[UserName] [nvarchar](64) NOT NULL,
[TimeStamp] [datetime] NOT NULL,
[SessionId] [uniqueidentifier] NOT NULL,
[Action] [nvarchar](50) NOT NULL,
[ActionId] [uniqueidentifier] NOT NULL,
[Description] [nvarchar](256) NOT NULL,
CONSTRAINT [PK_Timer] PRIMARY KEY CLUSTERED
(
[TimerId] ASC
)
LINQ的模型(有删节):
The LINQ model is (abridged):
public partial class Timer
{
[Column(AutoSync=AutoSync.OnInsert, DbType="Int NOT NULL IDENTITY", IsPrimaryKey=true, IsDbGenerated=true)]
public int TimerId { get; set; }
[Column(DbType = "NVarChar(64) NOT NULL", CanBeNull = false)]
public string UserName { get; set; }
[Column(DbType = "DateTime NOT NULL")]
public DateTime TimeStamp { get; set; }
[Column(DbType = "UniqueIdentifier NOT NULL")]
public Guid SessionId { get; set; }
[Column(DbType = "NVarChar(50) NOT NULL", CanBeNull = false)]
public string Action { get; set; }
[Column(DbType = "UniqueIdentifier NOT NULL")]
public Guid ActionId { get; set; }
[Column(DbType = "NVarChar(256) NOT NULL", CanBeNull = false)]
public string Description { get; set; }
}
和违规code为(有删节):
And the offending code is (abridged):
using (var ctx = new MyDataContext())
{
var timer = new Timer();
timer.Action = "Start";
timer.ActionId = Guid.NewGuid();
timer.Description = "foo";
timer.SessionId = Guid.NewGuid();
timer.TimeStamp = DateTime.UtcNow;
timer.UserName = "foo";
ctx.Timers.InsertOnSubmit(timer);
ctx.SubmitChanges(); // exception thrown here
}
该错误消息说 System.InvalidCastException:指定强制转换为无效
,但它没有提到该属性导致了这一问题。任何人都可以发现其属性导致我的问题?
The error message says System.InvalidCastException: Specified cast is not valid.
but it doesnt mention which property is causing the problem. Can anyone spot which property is causing me problems?
我的表中删除,重新创建它,刷新我的模型,一切都开始工作,而无需改变任何东西。我不认为有什么改变,但很明显,.NET又喜欢我。
I dropped the table, recreated it, refreshed my model and everything started working without having to change anything else. I dont think anything changed, but clearly .NET likes me again.