由网友(素染倾城色)分享简介：下面code尝试创建一个新的记录，然后修改它后，它已被提交到数据库。最后的SubmitChanges（）调用抛出一个ChangeConflictException。The following code tries to create a new record and then modify it after it h...

下面code尝试创建一个新的记录，然后修改它后，它已被提交到数据库。最后的SubmitChanges（）调用抛出一个ChangeConflictException。

The following code tries to create a new record and then modify it after it has been committed to the database. The last SubmitChanges() call throws a ChangeConflictException.

ItemA itemA = new ItemA();
itemA.Foo = "a";
itemA.Created = DateTimeOffset.Now.UtcDateTime;

ItemAs.InsertOnSubmit(itemA);
SubmitChanges();

itemA.Foo = "b";
SubmitChanges();

通过研究我发现，创造列是冲突的，即使报道CurrentValue的和DatabaseValue出现相同的dataContext.ChangeConflicts。在仔细检查我发现蜱略有不同。因为我已经设置的DateTimeOffset列在数据库中有一个规模为3，即毫第二，它是不一样的.NET版本，我相信有规模的7。因此LINQ到SQL中的价值注意到的不匹配，认为之间的插入和更新上面显示，事情已经修改了数据库。

By examining the dataContext.ChangeConflicts I found that the 'Created' column was in conflict, even though the reported CurrentValue and DatabaseValue appeared identical. On closer inspection I found that the Ticks were slightly different. Because I have set the DateTimeOffset column in the database to have a scale of 3, i.e. to the milli second, it is not the same as .NET's version of the value which I believe has a scale of 7. As a result Linq to Sql notices the mismatch and thinks that between the insert and update shown above, something has modified the database.

除了写一个extentension方法或东西，我可以用它来修改precision在.NET中有没有更好的方式来处理这个？

Aside from writing an extentension method or something that I can use to modify the precision in .NET is there a better way to deal with this?

更新

我不得不依靠它必须设置该模型的DateTimeOffset列时，称为扩展方法。

I have had to rely on an extension method which must be called when setting DateTimeOffset columns on the model.

public static DateTimeOffset ToUniversalTime(this DateTimeOffset dto, int scale) {
    DateTimeOffset utc = dto.ToUniversalTime();
    return utc.AddTicks(-(utc.Ticks % (int)Math.Pow(10, 7 - scale)));
}

然后可以称为：

Which can then be called as:

EntityFoo.Created = DateTimeOffset.Now.ToUniversalTime(3)

我真的不喜欢这种方法，因为这意味着我必须手动设置我相信数据方面应该做的规模。

I don't really like this approach as it means I have to manually set the scale which I believe the data context should be doing.

推荐答案

由于你总是用世界时，我看不到有什么优势的DateTimeOffset为您提供了日期时间。你可以使用DateTime.UtcNow，具有相同的precision作为SQL Server的日期时间。

As you're always using Universal Time, I can't see what advantage DateTimeOffset gives you over DateTime. You could use DateTime.UtcNow, which has the same precision as Sql Server's DateTime.

另外，如您使用的是SQL Server 2008中，您可以在字段中存储为DATETIME2在数据库中：这有您所需要的额外精度

Alternatively, as you're using Sql Server 2008, you could store your field as a DateTime2 in the database: this has the additional accuracy you require.