使用ADO.net实体框架4枚举？我该怎么办呢？ [英] Using ADO.net Entity Framework 4 with Enumerations? How do I do it?

问题描述

问题1：我玩弄EF4和我有一样的模型类：

Question 1: I am playing around with EF4 and I have a model class like :

public class Candidate {

public int Id {get;set;}
public string FullName {get;set;}
public Gender Sex {get;set;}
public EducationLevel HighestDegreeType {get;set;}
}

下面的性别与EducationLevel就像枚举：

Here Gender and EducationLevel are Enums like:

public enum Gender {Male,Female,Undisclosed}
public enum EducationLevel {HighSchool,Bachelors,Masters,Doctorate}

如何获得候选类和性别与EducationLevel与EF4工作，如果：

How do I get the Candidate Class and Gender and EducationLevel working with EF4 if:

• 在我做的模型首次开发
• 在我做的第一个数据库开发

编辑：涉及到对象上下文另一个问题here.

Moved question related to object context to another question here.

推荐答案

显然 INT＆LT; - ＆GT;枚举 <一个href="http://social.msdn.microsoft.com/Forums/en-US/adonetefx/thread/7659feab-d348-4367-b2cd-0456b20262fe">won't在EF的初始版本将支持中4。我同意那些谁这样说很烂。

Apparently int <-> enum won't be supported in the initial release of EF4. I agree with those who say this sucks.

我使用的是做铸件为我的属性

I am using a property that does the casting for me

public partial class MyEntity
{
  public MyEnum HurrEnum {get{return (MyEnum)Hurr;} set{Hurr = (int)value;}}
}

它看起来并不那么糟糕，如果你的名字的东西正确（这意味着，所以它看起来并不愚蠢）。举例来说，我有一个储存在数据库中的一个原因原因code枚举，所以我有物业的理性与理性code版本。作品出来不够好，现在是这样。

It doesn't look so bad if you name stuff "correctly" (which means, so it doesn't look stupid). For instance, I have a ReasonCode enum that's stored as a Reason in the database, so I have Reason and ReasonCode versions of the property. Works out well enough, for now.

首先，我刚开始使用EF4所以我不亲近它是如何工作。我认为它类似于L2S但具有更好的实体支持。与盐，粮借此的

需要明确的是，这个属性是为了方便起见，我90％肯定，如果你尝试使用这个属性来查询数据库EF会产生不良反应。 EF不知道你的财产，不能用它来构造SQL。所以这样的：

To be clear, this property is for convenience and I'm 90% sure EF will react badly if you try to query the database using this property. EF doesn't know about your property and cannot use it to construct sql. So this:

var foo = from x in Db.Foos where x.HurrEnum == Hurr.Durr select x;

将可能无法按预期在哪里这样的：

will probably fail to behave as expected where this:

var foo = Db.Foos.Where(x=> x.HurrEnum == Hurr.Durr);

可能会导致整个FOOS表被带入内存中，然后进行解析。 此属性是为了方便起见，应使用的数据库已经被打后才如：！

 // this is executed in the sql server
 var foo = Db.Foos.Where(x=> x.Hurr == 1 || x.Hurr == 2).ToArray();
 // this is then done in memory
 var hurrFoos = foo.Where(x=> x.HurrEnum == Hurr.Durr);

如果你不明白这里的区别是，你在玩火。你需要学习如何EF / L2S除$ P $其中pts您code并将其转换成SQL语句。

If you don't understand the difference is here then you're playing with fire. You need to learn how EF/L2S interprets your code and converts it into sql statements.

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