我正在尝试更新 CustomerRailcard 对象，该对象对 Railcard 对象的引用以 end * 为 1。问题是，我无法删除 Railcard 对象，我只需将 CustomerRailcard 对象上的引用更改为另一个 RailcardObject。我这样做是这样的：
更新：
// Updating properties in existing CustomerRailcard.
// This won't update navigation properties (Railcard).
context.ObjectStateManager.ChangeObjectState(existingCustomerRailcard, EntityState.Modified);
context.ApplyCurrentValues("CustomerRailcardsDbo", newCustomerRailcard);
// Now I'm trying to update navigation property of CustomerRailcard to the Railcard
// by removing the reference from old Railcard to CustomerRailcard.
// Railcard can have references to many CustomerRailcards.
var oldRailcard = railcardRepository.FindById(customerDetails.CustomerRailcards.FirstOrDefault(r => r.Id == railcard.Id).Railcard.Id);
var customerRailcardToRemove = oldRailcard.CustomerRailcards.FirstOrDefault(cr => cr.Id == railcard.Id);
// Removing reference to CustomerRailcard from Railcard
oldRailcard.CustomerRailcards.Remove(customerRailcardToRemove);
// Now I'm getting new Railcard I want to have referenced by CustomerRailcard
// and I'm changing its reference tu CustomerRailcard
var newRailcard = railcardRepository.FindById(railcard.Railcard.Id);
// Adding reference to CustomerRailcard
newRailcardDboReference.CustomerRailcards.Add(railcard);
运行后我会得到这个错误
来自“CR_RL_FK”关联集的关系处于“已删除”状态。给定多重约束，相应的“CustomerRailcardDbo”也必须处于“已删除”状态。
我还应该如何对这种关系进行更新？