Question

I’ve got this piece of code to create new objects in a generic way:

var user = User.Create<User>(c => c.Name = "321X");

What I don’t like about it is the fact I need to pass the ‘generic notation’ <T> for every create call. After all I create an object that I’m already referring to…

The code behind this current functionality is:

public class User : CreateBase
{
    public string Name { get; set; }
}

public abstract class CreateBase
{
    public DateTime CreateDate { get; set; }
    public Guid Guid { get; set; }

    public static T Create<T>(Action<T> init) where T : CreateBase, new()
    {
        T obj = new T();
        obj.Guid = Guid.NewGuid();
        obj.DateTime = DateTime.Now;
        init(obj);
        return obj;
    }
}

Is it possible (and how) to refactor my code to this, to create an object?

var user = User.Create(c => c.Name = "321X");

Thanks!

Answer 1

Define the generic argument on the class level:

public abstract class CreateBase<T> where T : CreateBase<T> , new()
{
    public static T Create(Action<T> init) 
    {
        //...
    }
}

public class User : CreateBase<User>
{
    public string Name { get; set; }
}

Then you can write var user = User.Create(c => c.Name = "321X");

Otherwise the compiler cannot infer the type for your Create method without specifying the type argument.