Question

Assume some domain and view objects (that have no common base class)

public class DomainA
{
    public int MyProperty { get; set; }
}

public class ViewA
{
    public int MyProperty { get; set; }
}

public class DomainB
{
    public string MyProperty { get; set; }
}

public class ViewB
{
    public string MyProperty { get; set; }
}

and a class that can convert from domain to corresponding view

public class ViewFactory
{
    public static ViewA Create(DomainA value)
    {
        return new ViewA() { MyProperty = value.MyProperty };
    }

    public static ViewB Create(DomainB value)
    {
        return new ViewB() { MyProperty = value.MyProperty };
    }
}

Is it possible to write a method along the lines of

public static List<T> Create<T, U>(IEnumerable<U> values)
{
    return new List<T>(from v in values where v != null select Create((U)v));
}

that can convert lists of the “domain” objects to lists of the “view” objects given that there are already methods for converting a single object?

I feel like I’m missing something really stupid and basic about generics asking this question..better to learn the answer than remain clueless though 🙂

Answer 1

Yes if you modify your Create function to take a mapping between domain and views:

public static List<T> Create<T, U>(IEnumerable<U> values, Func<U, T> mapFunc)
{
    return values.Select(v => mapFunc(v)).ToList();
}

You can then do the mapping using your ViewFactory methods:

IEnumerable<DomainA> domAs = //whatever
var aViews = Create(domAs, a => ViewFactory.Create(a));