LINQ to SQL附加实体问题 [英] LINQ to SQL attach entity issue

问题描述

我正在尝试在通用存储库中创建更新方法作为数据访问层
我有一个这样的实体:

I''am trying to create an update method in a generic repository as a data access layer
i have an entity like this:

[Table]
public class Product
{
    [Column(IsPrimaryKey = true, IsDbGenerated = true, DbType = "Int NOT NULL IDENTITY")]
    public int Id { get; private set; }
    [Column(UpdateCheck = UpdateCheck.Never)]
    public string Name { get; set; }
    ....
}

我为id以外的所有字段都设置了"Update Check = true"，并在attach方法中将"asModified"属性设置为true，结果如下:

i set `Update Check = true` for all the fields exept for the id and i set the `asModified` propery in the attach method to true which i found as following:

    public void Update(T entity)
    {
        _db.GetTable<t>().Attach(entity, true); 
        _db.SubmitChanges();
    }
</t>

但我不断遇到同样的异常:

如果实体声明了版本成员或没有更新检查策略，则只能将其以修改后的形式附加而没有原始状态.

那是什么问题呢?
或除了建立时间戳列作为版本号之外，是否建议其他方法在通用存储库中创建更新方法.

在此先感谢；

but i keep getting the same exception:

An entity can only be attached as modified without original state if it declares a version member or does not have an update check policy.

so what''s the problem ???
or Do you recommend any other approches to create an update method in a generic repository except createing a timestamp column as a version number.

Thanks in Advance;

推荐答案

在该表中包含一个时间戳列.会做到的.我的意思是时间戳数据类型.您可以随心所欲地调用它，例如. ts.

另外，我建议您查看LINQ的断开实体更改跟踪: http://linq2sqleb.codeplex.com/ [ ^ ]

Thx

include a timestamp column in that table. that will do it. I mean the timestamp data type. u can call it whatever u want, for eg. ts.

Else i sugesst you take a look at Disconnected Entity Change Tracking for LINQ: http://linq2sqleb.codeplex.com/[^]

Thx

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