我收到此錯誤後,點擊保存(更新)我的表格:的關係無法改變,因爲一個或多個外鍵的屬性是MVC非空的4
的關係無法因爲一個或多個外鍵屬性是不可空的而被更改。當對關係進行更改時,相關的外鍵屬性將設置爲空值。如果外鍵不支持空值,則必須定義新的關係,必須爲外鍵屬性指定另一個非空值,或者必須刪除不相關的對象。
這裏是我的控制器(案 「保存」 在SWICH淡然的問題):
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit(UserModel userModel, string act = null, int idx = 0)
{
using (var dbContext = new userDbEntities())
{
if (userModel.User == null)
{
userModel.User = new UsersTable();
}
var newUser = userModel.User.userID == 0;
userModel.CustomTypes = dbContext.CustomTypes.ToList();
switch (act)
{
case "addcustom":
userModel.User.CustomerTables.Add(new CustomerTable
{
CustomType = new CustomType(),
UsersTable = userModel.User
});
break;
case "deletecustom":
userModel.User.CustomerTables.RemoveAt(idx);
break;
case "save":
foreach (var customer in userModel.User.CustomerTables)
{
customer.CustomType = dbContext.CustomTypes.Find(customer.CustomType.Id_NewCustomerType);
}
var dbUser = dbContext.UsersTables.Find(userModel.User.userID);
dbUser.TimeZoneId = userModel.User.TimeZoneId;
foreach (var custom in userModel.User.CustomerTables)
{
if (custom.CustomerID == 0)
dbUser.CustomerTables.Add(custom);
}
foreach (var custom in dbUser.CustomerTables.ToList())
{
var modelCustom =
userModel.User.CustomerTables.FirstOrDefault(o => o.CustomerID == custom.CustomerID);
if (modelCustom != null) //update it
{
custom.CustomType =
dbContext.CustomTypes.Find(modelCustom.CustomType.Id_NewCustomerType);
}
if (userModel.User.CustomerTables.All(o => o.CustomerID != custom.CustomerID))
dbUser.CustomerTables.Remove(custom);
}
dbContext.SaveChanges();
break;
} // end switch statements
return View("Edit", userModel);
}
}
任何想法是錯誤的...
好的,如果改變dbUser.CustomerTables.Remove(custom);到dbContext.Entry(自定義).State = EntityState.Deleted;修復問題,但然後簡單添加(保存不起作用) –
可能重複的[該關係無法更改,因爲一個或多個外鍵屬性是不可空](http://stackoverflow.com/questions/5538974/the-relationship-could-be-changed-because-one-more-the-the-foreign-key-pro) –