Entity Framework 4.1 Code First mapping/populating a single property from two db columns

Question

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

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.

I have a simple class

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; }
}

and a mapping file that looks like

     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

    }
}

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

Ladislav Mrnka · Accepted Answer · 2011-05-19 21:54:32Z

2

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; }
}

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).

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.

answered May 19, 2011 at 21:54

Ladislav Mrnka

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3 Comments

DDiVita Over a year ago

You can still filter by it, as long as the entity collection is in memory, correct?

Ladislav Mrnka Over a year ago

Yes you can filter by it when using linq to objects

waa Over a year ago

Thanks. embarrassed i asked. forest from the trees issue on my end.

Steve Mallory · Accepted Answer · 2011-05-19 21:49:00Z

1

I wouldn't map the field in the database. Instead, I would declare my POCO as partial. In another file, I would have the same partial class and define the combination value there (with only a getter). I have sample code if you need it.

Keeping it in a separate file helps if you do any code generation later.

answered May 19, 2011 at 21:49

Steve Mallory

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1 Comment

Andrew Over a year ago

Can you post an example of this in action? Would be useful for others

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