Object to object mapper

Question

I've used plenty of ORM tools in the past, NHibernate, .netTiers, LLBLGen and more and they always do a pretty good job of mapping data from a database to objects in code.

What I'm looking for though is a framework or a pattern or something that will allow me to transform objects from one type to another.

An example is I have a two web services, one has Investors another has Members. I want to convert an Investor object to a Member object by defining a set of rules that maps the Investor properties to the Member properties and back again.

NHibernate mappings are the closest I can get to doing this, but it only seems to work for Database -> Object mappings. I was wondering if anyone knew of any products that allowed me to do obejct -> object mapping?

Answer 1

You can use .NET Serialization to serialize one type to another provided they share a common contract.

MSDN has a lot of good info:

http://msdn.microsoft.com/en-us/library/system.runtime.serialization.aspx

Specifically, DataContractSerializer.

Answer 2

Jonathan mentions data-contracts, which is a good option. I guess part of the reason that there isn't massive support for this is that it is already fairly easy to do through code, for example via a conversion operator (although a regular instance method would work just as well, and arguably be clearer) ...

class Foo {
    public string Name { get; set; }
    /* etc */
}

class Bar {
    public string Caption { get; set; }
    /* etc */

    public static explicit operator Foo(Bar bar) {
        return new Foo { Name = bar.Caption /* etc */};
    }
    public static explicit operator Bar(Foo foo) {
        return new Bar { Caption = foo.Name /* etc */};
    }
}

If you don't control the classes (and partial classes aren't an option), then in C# 3.0 you could use an extension method to simulate an instance method:

public static Foo ToFoo(this Bar bar) {
    return new Foo { Name = bar.Caption /* etc */};
}
public static Bar ToBar(this Foo foo) {
    return new Bar { Caption = foo.Name /* etc */};
}

Answer 3

You are looking for AutoMapper

http://automapper.codeplex.com/

Answer 4

There is the Otis project that is similar to AutoMapper but it does its thing using attributes.

Answer 5

Take a look on http://emitmapper.codeplex.com It faster and more flexible than automapper.