[英]ASP.NET C# Entity Framework - How to update Foreign Key properly? - Part 2
這是我學到的並希望成為現實的事情:
這是我修改的代碼:
public class ManagerBase
{
private NoxonEntities _entities = null;
public NoxonEntities Entities
{
get
{
if (_entities == null)
_entities = new NoxonEntities();
return _entities;
}
}
}
//Managers uses ManagerBase class as a Base class
MemberManager currentMemberManager = new MemberManager();
currentMemberManager.Save(memberId, username, password, languageId);
//MemberManager class
public Member Save(long memId, string username, string password, int langId)
{
using (var Context = base.Entities)
{
var Data = Context.Member.First(c => c.Id == memId);
Data.Username = username;
Data.Password = password;
Data.Language = Context.Language.First(c => c.Id == langId); //Gets the foreign entity
Context.SaveChanges();
return Data;
}
}
這毫無例外地起作用。 但通常,此SAVE方法是通過接口實現的方法。 所以,我寧願一個對象值傳遞給save方法不是將所有的領域,如上述。 例如,我想使用這個:
//Member is an EntityFramework Object which was created during EF Model when I added by visual studio
//Filter is the method that returns an EntityFramework Object from EF (and eventually database) with given some arguments
//SomeArguments could be MemberId = 2
Member modifiedMember = currentMemberManager.Filter(someArguments);
modifiedMember.UserName = "newvalue";
currentMemberManager.Save(modifiedMember);
在SAVE方法中,也許我可以這樣使用:
public Member Save(Member modifiedMember)
{
using (var Context = base.Entities)
{
var Data = Context.Member.First(c => c.Id == modifiedMember.Id);
Data.Username = modifiedMember.Username;
Data.Password = modifiedMember.Password;
Data.Language = Context.Language.First(c => c.Id == modifiedMember.LanguageId); //Gets the foreign entity
Context.SaveChanges();
return Data;
}
}
如果我要像上面的右一個那樣使用它,我想我不應該使用傳遞對象EF Object,而是應該使用我將要編寫的其他一些類來將參數映射到EF Member Entity。
第一個問題:這是一個好方法嗎?
public class MyMember
{
public long Id { set; get; }
public string Username { set; get; }
public string Password { set; get; }
public int LanguageId { set; get; }
}
MyMember.Username = "NewValue";
MyMember.LanguageId = 4; //4 as in new value
currentMemberManager.Save(MyMember); //As you can see MyMember is not an EF Entity in here
但這將花費很長時間,因為已經有一些書面代碼。
第二個問題:我不能境外使用的EF實體對象,然后修改它那里將其保存在 MemberManager類?
再次感謝您的提前幫助。
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