c# - 为什么这个带 IDENTITY_INSERT 的 EF 插入不起作用？

Question

这是查询:

using (var db = new AppDbContext())
{
    var item = new IdentityItem {Id = 418, Name = "Abrahadabra" };
    db.IdentityItems.Add(item);
    db.Database.ExecuteSqlCommand("SET IDENTITY_INSERT Test.Items ON;");
    db.SaveChanges();
}

执行时，新表中插入记录的Id仍为1。

新:当我使用事务或 TGlatzer 的答案时，我得到异常:

Explicit value must be specified for identity column in table 'Items' either when IDENTITY_INSERT is set to ON or when a replication user is inserting into a NOT FOR REPLICATION identity column.

Answer 1

根据之前的Question您需要开始您的上下文事务。保存更改后，您还必须重新声明 Identity Insert 列，最后您必须提交事务。

using (var db = new AppDbContext())
using (var transaction = db .Database.BeginTransaction())
{
    var item = new IdentityItem {Id = 418, Name = "Abrahadabra" };
    db.IdentityItems.Add(item);
    db.Database.ExecuteSqlCommand("SET IDENTITY_INSERT Test.Items ON;");
    db.SaveChanges();
    db.Database.ExecuteSqlCommand("SET IDENTITY_INSERT Test.Items OFF");
    transaction.Commit();
}