Question

I am looking to find a way to take two objects that have identical properties and make a call to copy the property values from one object into the other. The the example below assume I have an instance of A and I want to use the data of that instance to hydrate a new instance or C (to keep things terse I used fields instead of properties in the example below)

public class A : B
{
    public string prop1;
    public int prop2;
}

public class B
{
    public byte propX;
    public float propY;
}

public class C
{
    public byte propX;
    public float propY;
    public string prop1;
    public int prop2;
}

public class Merger
{
    public static object Merge(object copyFrom, object copyTo)
    { 
        //do some work
        //maybe <T> generically refactor?
    }
}

The merger class is just a psuedo-example, doing this through generics would be optimal but the first thing I question is whether such a capability already exists. I could imagine using reflection to do this myself but just wanted to toss it out for better ideas first.

Real world context: This is actually an MVVM related issue as I am trying to use disparate classes coming back from EF to populate a ViewModel instance.

Answer 1

Check out tools and libraries like AutoMapper – those would handle cases like this with ease – and much more! No need to re-invent the wheel – just use the tool! 🙂

You would basically define a map between classes A and C like this:

Mapper.CreateMap<A, C>();

and then later on, you can have AutoMapper do the mapping, based on that map, from an instance of A into an instance of C, something like this:

C yourC = Mapper.Map<A, C>(instanceOfA);

AutoMapper does a default mapping based on property names (and types), but you can extend and influence it in a great many ways to include mappings from one property to another, even if the names (or types) don’t match 100%. It’s quite flexible and well established – definitely worth a serious look!