ObjectStateManager没有定义问题

Question

我面临着问题ObjectStateManager。

我都是using，System.Data.Entity但是System.Data.Objects它没有显示 的​​定义ObjectStateManager。

SampleContext db = new SampleContext();
Employees employeeFromDB = db.Employees.Single(x => x.Id == employee.Id);

employeeFromDB.FullName = employee.FullName;
employeeFromDB.Gender = employee.Gender;
employeeFromDB.Age = employee.Age;
employeeFromDB.HireDate = employee.HireDate;
employeeFromDB.Salary = employee.Salary;
employeeFromDB.PersonalWebSite = employee.PersonalWebSite;

db.ObjectStateManager.ChangeObjectState(employeeFromDB, System.Data.EntityState.Modified);
db.SaveChanges();
return RedirectToAction("Details", new {Id = employee.Id});

Answer 1

来自：为什么我的数据库上下文中不存在 ObjectStateManager 属性？

var manager = ((IObjectContextAdapter)db).ObjectContext.ObjectStateManager;