我试图以下列方式执行EF更新,但继续收到此错误：
只有当属性的当前值为null时,才能设置EntityKey属性.
- using (hydraEntities db = new hydraEntities())
- {
- YouUser = db.youusers.Include("address").Include("entity").Include("youusercontacts.contact").Include("youuserlogins").Include("youusernotes.note").Include("youusernotes.youuser.entity").Where( yu => yu.YOUUserId.Equals(YOUUserId)).First();
- }
- YouUser.entity.FirstName = txtFirstName.Text;
- YouUser.entity.LastName = txtLastName.Text;
- YouUser.address.AddressLine1 = txtAddressLine1.Text;
- YouUser.address.AddressLine2 = txtAddressLine2.Text;
- YouUser.address.City = txtCity.Text;
- YouUser.address.State = ddlState.SelectedValue;
- YouUser.address.Zipcode = txtZipcode.Text;
- using (hydraEntities db = new hydraEntities())
- {
- db.youusers.AddObject(YouUser);
- db.ObjectStateManager.ChangeObjectState(YouUser,System.Data.EntityState.Modified);
- db.SaveChanges();
- }
非常感谢我如何解决这个问题并执行上述声明.
解决方法
在此方案中不要使用AddObject.它用于插入新实体,但您正在更新现有实体.改为使用Attach：
- using (hydraEntities db = new hydraEntities())
- {
- db.youusers.Attach(YouUser);
- db.ObjectStateManager.ChangeObjectState(YouUser,System.Data.EntityState.Modified);
- db.SaveChanges();
- }
