EF 7 身份插入问题 [英] EF 7 Identity Insert Issue

问题描述

我必须能够设置要添加到列表final_zones"中的实体的主键.我有一个控制器构造函数，如下所示:

I have to be able to set the primary key of the entities I am trying to add in my list "final_zones". I have a controller constructor as follows:

    public UtilController(CFETSContext context)
    {
        _context = context; 
    }
     ......Then in a web api method.........
        using (var transaction = _context.Database.BeginTransaction())
        {
            _context.Database.ExecuteSqlCommand(@"SET IDENTITY_INSERT [CFETSWeb].[dbo].[Zone] ON");             

            _context.SaveChanges();
            transaction.Commit();
        }


       using (var transaction = _context.Database.BeginTransaction())
        {             
            _context.Zones.AddRange(final_zones);
            _context.SaveChanges(); //ERROR HERE
            transaction.Commit();
        }

无论我做什么，我似乎都无法打开 IDENTITY_INSERT.我收到以下错误:

No matter what I do, I cannot seem to get IDENTITY_INSERT to turn on. I get the following error:

{"Cannot insert explicit value for identity column in table 'Zone' when IDENTITY_INSERT is set to OFF."}

我似乎无法关闭它.我可以在控制器中将实体添加到我的数据库中，所以我知道其他一切都在工作.我也尝试过在没有事务的情况下执行此操作，结果相同.

I just can't seem to get it to turn off. I can add entities to my DB in the controller, so I know everything else is working. I have tried doing this without a transaction as well with the same result.

 _context.Database.ExecuteSqlCommand(@"SET IDENTITY_INSERT [CFETSWeb].[dbo].[Zone] ON"); 
_context.Zones.AddRange(final_zones);
        _context.SaveChanges();

有什么想法吗?我不知道接下来要尝试什么.谢谢.

Any ideas? I am at a loss for what to try next. Thanks.

推荐答案

我用以下方法解决了:

       using (var dbContextTransaction = _context.Database.BeginTransaction())
        {
            try
            {
                _context.Database.ExecuteSqlCommand(@"SET IDENTITY_INSERT [CFETSWeb].[dbo].[Zone] ON");
                _context.Zones.AddRange(final_zones);
                _context.SaveChanges();          

                dbContextTransaction.Commit();
            }
            catch (Exception e)
            {
                dbContextTransaction.Rollback();
            }
        }

注意:您必须每张桌子都这样做.IDENTITY_INSERT 似乎一次只能为 1 个表设置，因此您可以这样做或在同一事务中将其切换为 OFF.

NOTE: You HAVE to do this per table. IDENTITY_INSERT can only be set for 1 table at a time it seems, so you can do it this way or toggle it to OFF in the same transaction.

此外，IDENTITY_INSERT 必须在事务中，因为它只在事务期间保持打开状态.

Also, IDENTITY_INSERT has to be in a transaction, as it only stays on for the duration of a transaction.

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