实体框架4.1代码优先从两个数据库列映射/填充单个属性 [英] Entity Framework 4.1 Code First mapping/populating a single property from two db columns

问题描述

我知道这个问题已经被问到/回答了，但是我一生都找不到.

I know this question has been asked/answered but I can't find it for the life of me.

我正在使用现有数据库创建ASP.NET MVC 3应用程序，但想先编写代码，所以我使用EF Power Tools CTP1入门.最终，我将重构为一个更好的解决方案，但是要开始使用，我使用MVCScaffolding生成了控制器和视图.我正在努力在模型上创建显示值(FullName)属性，该属性是数据库中FirstName和LastName列的组合.

I am creating and ASP.NET MVC 3 app with an existing db but wanted to go code first so I'm used the EF Power Tools CTP1 to get me started. Ultimately, I will refactor to a better solution but to get going I used the MVCScaffolding to gen up controllers and views. I'm struggling with creating a display value (FullName) property on my model that is a combination of the FirstName and LastName columns in the DB.

我有一个简单的课程

public class Manager
{
    public Manager(){}

    public int ManagerID { get; set; }

    [DisplayName] // Not in db.. want to populate this from first & last name 
    public  string FullName { get; set; }

    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
}

和看起来像

     public ManagerMap()
    {
        // Primary Key
        this.HasKey(t => t.ManagerID);

        // Table & Column Mappings
        this.ToTable("Manager");
        this.Property(t => t.ManagerID).HasColumnName("ManagerID");

        this.Property(t => t.FirstName).HasColumnName("FirstName");
        this.Property(t => t.LastName).HasColumnName("LastName");
        this.Property(t => t.Email).HasColumnName("Email");
        this.Property(t => t.FullName).WhatToDo..? //<-- Can I / how does this mapping look

    }
}

是否可以创建FullName映射，还是我要以完全错误的方式进行此操作?

Is it possible to create the FullName mapping or am I going about this the entirely wrong way?

推荐答案

否，无法创建FullName映射.但是您可以使用以下简单的解决方法:

No it is not possible to create FullName mapping. But you can use this simple workaround:

public class Manager
{
    public Manager(){}

    public int ManagerID { get; set; }

    [NotMapped]
    public string FullName 
    { 
       get
       {
           return FirstName + " " + LastName;
       }
    }

    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
}

此方法的唯一缺点是您不能在linq-to-entities查询中使用FullName属性(因此，例如，您无法使用FullName进行订单或搜索-您仍必须使用FirstName和LastName ).

The only disadvantage of this approach is that you cannot use FullName property in linq-to-entities query (so you cannot for example order or search by FullName - you must still use FirstName and LastName).

如果您使用新的Power Tools的代码生成功能，则应按照@Steve Mallory的建议，在单独的部分类中声明此属性-如果要重新生成，请不要修改生成的代码.

If you use code generation feature of new Power Tools you should really declare this property in separate partial class as proposed by @Steve Mallory - don't modify generated code if you ever want to regenerate it.

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