向EF添加新实体时出错:发生了参照完整性约束违规

Question

我正在添加一个通过外部类构建的新实体,我收到此错误 A referential integrity constraint violation occurred: A primary key property that is a part of referential integrity constraint cannot be changed when the dependent object is Unchanged unless it is being set to the association's principal object. The principal object must be tracked and not marked for deletion.:

编辑:ReconFact实体未链接到任何其他实体

代码(已编辑):

// the context class
AccountingModelContext db = new AccountingModelContext();
// query some data
List<Reconciliation> recon = db.Reconciliations
        .Where(r => r.ReconNum == 112293)  // scenario 18 
        .Include(r => r.ReconciliationDetails.Select(rd => rd.JrnlEntryDetail).Select(jd => jd.JrnlEntry).Select(j => j.ARInvoices.Select(i => i.ARInvoiceDetails)))
        .Include(r => r.ReconciliationDetails.Select(rd => rd.JrnlEntryDetail).Select(jd => jd.JrnlEntry).Select(j => j.ARCredMemoes.Select(c => c.ARCredMemoDetails)))
        .ToList();
// class that will manager business logic and generate facts with above data
ReconFactGenerator generator = new ReconFactGenerator(recon);
// call to the method that will return a list of facts
List<ReconFact> scenario18 = generator.GenerateFacts();
// ERROR RAISED HERE
scenario18.ForEach(f => db.ReconFacts.Add(f));
// never reached
db.SaveChanges();

这是非常基础的我ReconFact用ReconFactGenerator类构建实体列表.没有指定ID,因为它们是新实体.

编辑 如果我在这里使用相同的方法创建一个新实体,那么它是完美的.在我从上下文查询数据之前:

ReconFact testfact = new ReconFact { ItemCode = "test", ReconNum = 1234, ReconDate = DateTime.Parse("2099-01-01"), ShortName = "L_SZTREDFD", InvoiceAmount = 0, CredMemoAmount = 0, IncomingPayAmount = 0, OutgoingPayAmount = 0, JrnlEntryAmount = 0, OtherAmount = 0 };
db.ReconFacts.Add(testfact); // no problems no error raised
db.SaveChanges(); // I can see the new record in my database 
                  // the ID was generated successfully 
                  // as I've specified identity(1,1) in the database

添加编辑2 在我从上下文查询数据后,如下所示:

 List<Reconciliation> recon = db.Reconciliations
        .Where(r => r.ReconNum == 112293)  // scenario 18 
        .Include(r => r.ReconciliationDetails.Select(rd => rd.JrnlEntryDetail).Select(jd => jd.JrnlEntry).Select(j => j.ARInvoices.Select(i => i.ARInvoiceDetails)))
        .Include(r => r.ReconciliationDetails.Select(rd => rd.JrnlEntryDetail).Select(jd => jd.JrnlEntry).Select(j => j.ARCredMemoes.Select(c => c.ARCredMemoDetails)))
        .ToList();

上下文无法再保存以返回上述错误.

编辑为什么在查询上下文后我想保存时出现错误并且之前没有引发错误？

Answer 1

找到了解决方法，尽管它没有解释为什么会发生错误：

// the context class
AccountingModelContext db = new AccountingModelContext();
// query some data
List<Reconciliation> recon = db.Reconciliations
        .Where(r => r.ReconNum == 112293)  // scenario 18 
        .Include(r => r.ReconciliationDetails.Select(rd => rd.JrnlEntryDetail).Select(jd => jd.JrnlEntry).Select(j => j.ARInvoices.Select(i => i.ARInvoiceDetails)))
        .Include(r => r.ReconciliationDetails.Select(rd => rd.JrnlEntryDetail).Select(jd => jd.JrnlEntry).Select(j => j.ARCredMemoes.Select(c => c.ARCredMemoDetails)))
        .ToList();
// class that will manager business logic and generate facts with above data
ReconFactGenerator generator = new ReconFactGenerator(recon);
// call to the method that will return a list of facts
List<ReconFact> scenario18 = generator.GenerateFacts();

// ERROR RAISED HERE
// scenario18.ForEach(f => db.ReconFacts.Add(f));

// INSTEAD OF REUSING THE CONTEXT I CREATE A NEW ONE PROBLEM SOLVED !
using (db = new AccountingModelContext())
{
  scenario18.ForEach(f => db.ReconFacts.Add(f));
  db.SaveChanges();
}
db.SaveChanges();