C# 英孚核心；无法为标识列“插入显式值”；虽然IDENTIY_INSERT设置为ON

我正在使用EntityFrameworkCore2.1，希望使用IDENTITY\uInsert插入一些数据。 虽然我将IDENTITY_INSERT设置为On，但在

identityContext.SaveChanges（）行中仍然出现异常：

Microsoft.EntityFrameworkCore.DbUpdateException:'发生错误
在更新条目时。有关详细信息，请参阅内部异常。”

内部异常

SqlException:无法为插入显式值
当identity_INSERT设置为时，表“ClientGroups”中的identity列
走开

这是我的代码：

using (var identityContext = new IdentityDatabase(identityOptions))
{
    Console.WriteLine("Settings Identity Insert on");
    identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.ClientGroups ON");
    identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Clients ON");
    identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.ModulePermissions ON");
    identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Roles ON");
    identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Users ON");

    identityContext.Clients.AddRange(identityclients);
    identityContext.ClientGroups.AddRange(identityClientGroups);
    identityContext.ClientGroupAssociations.AddRange(identityClientGroupAssociations);
    identityContext.AuthClients.AddRange(identityAuthClients);
    identityContext.Roles.AddRange(identityRoles);
    identityContext.Users.AddRange(identityUsers);
    identityContext.UserRoles.AddRange(identityUserRoles);
    identityContext.ModulePermissions.AddRange(identityModulePermissions);
    Console.WriteLine("Saving Data to .identity Database");
    identityContext.SaveChanges();

    Console.WriteLine("Setting Identity Insert off");
    identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.ClientGroups OFF");
    identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Clients OFF");
    identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.ModulePermissions OFF");
    identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Roles OFF");
    identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Users OFF");
}

我打开了日志记录，可以看到命令已发送到数据库：

信息：Microsoft.EntityFrameworkCore.Database.Command[20101]
已执行的DbCommand（1ms）[参数=[]，命令类型='Text'，命令超时='30']
设置标识\u在以下信息上插入dbo.ClientGroups:Microsoft.EntityFrameworkCore.Database.Command[20101]
已执行的DbCommand（0ms）[参数=[]，命令类型='Text'，命令超时='30']
设置标识\u在信息上插入dbo.Clients:Microsoft.EntityFrameworkCore.Database.Command[20101]
已执行的DbCommand（0ms）[参数=[]，命令类型='Text'，命令超时='30']
设置标识\u在以下信息上插入dbo.ModulePermissions:Microsoft.EntityFrameworkCore.Database.Command[20101]
已执行的DbCommand（0ms）[参数=[]，命令类型='Text'，命令超时='30']
SET IDENTITY\u INSERT dbo.Roles ON info:Microsoft.EntityFrameworkCore.Database.Command[20101]
已执行的DbCommand（0ms）[参数=[]，命令类型='Text'，命令超时='30']
在上设置IDENTITY_INSERT dbo.Users

EF Core为每个与数据库相关的操作打开/关闭连接，因此使用
ExecuteSqlCommand
将标识设置为on无效

您需要在整个过程中明确保持连接打开：

identityContext.Database.OpenConnection();
try
{
    // your code …
}    
finally
{
    identityContext.Database.CloseConnection();
}

或者将整个流程包装在显式事务中：

using (var transaction = identityContext.Database.BeginTransaction())
{
    // your code …
    transaction.Commit();
}

这是一个混合的评论@damien的不信者和建议的答案@ivan stoev

一次只能为一个表启用IDENTITY_INSERT
代码必须包装在事务中，否则EF Core将使用单独的连接
这是密码

using (var identityContext = new IdentityDatabase(identityOptions))
{
    using (var transaction = identityContext.Database.BeginTransaction())
    {
        Console.WriteLine("Inserting AuthClients");
        identityContext.AuthClients.AddRange(identityAuthClients);
        identityContext.SaveChanges();

        Console.WriteLine("Inserting ClientGroups");
        identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.ClientGroups ON");
        identityContext.ClientGroups.AddRange(identityClientGroups);
        identityContext.SaveChanges();
        identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.ClientGroups OFF");

        Console.WriteLine("Inserting Clients");
        identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Clients ON");
        identityContext.Clients.AddRange(identityclients);
        identityContext.SaveChanges();
        identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Clients OFF");

        Console.WriteLine("Inserting ClientGroupAssociations");
        identityContext.ClientGroupAssociations.AddRange(identityClientGroupAssociations);
        identityContext.SaveChanges();

        Console.WriteLine("Inserting Users");
        identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Users ON");
        identityContext.Users.AddRange(identityUsers);
        identityContext.SaveChanges();
        identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Users OFF");

        Console.WriteLine("Inserting Roles");
        identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Roles ON");
        identityContext.Roles.AddRange(identityRoles);
        identityContext.SaveChanges();
        identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Roles OFF");

        Console.WriteLine("Inserting UserRoles");
        identityContext.UserRoles.AddRange(identityUserRoles);
        identityContext.SaveChanges();

        Console.WriteLine("Inserting ModulePermissions");
        identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.ModulePermissions ON");
        identityContext.ModulePermissions.AddRange(identityModulePermissions);
        identityContext.SaveChanges();
        identityContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.ModulePermissions OFF");

        Console.WriteLine("Commiting transaction");
        transaction.Commit();
    }
}

您的表在sql server中真的是这样命名的吗在任何时候，会话中只有一个表的IDENTITY_INSERT属性可以设置为ON。如果一个表已将此属性设置为“开”，并且为另一个表发出了set IDENTITY_INSERT ON语句，SQL Server将返回一条错误消息，说明set IDENTITY_INSERT已打开，并报告为“”设置的表。您的代码无法按编写的方式工作。