c# - Cannot implicitly convert derived type to its base generic type

Question

I have the following classes and interfaces:

public interface IThing
{
    string Name { get; }
}

public class Thing : IThing
{
    public string Name { get; set; }
}

public abstract class ThingConsumer<T> where T : IThing
{
    public string Name { get; set; }
}

Now, I have a factory that will return objects derived from ThingConsumer like:

public class MyThingConsumer : ThingConsumer<Thing>
{
}

My factory currently looks like this:

public static class ThingConsumerFactory<T> where T : IThing
{
    public static ThingConsumer<T> GetThingConsumer(){
        if (typeof(T) == typeof(Thing))
        {
            return new MyThingConsumer();
        }
        else
        {
            return null;
        }
    }
}

I'm getting tripped up with this error: Error 1 Cannot implicitly convert type 'ConsoleApplication1.MyThingConsumer' to 'ConsoleApplication1.ThingConsumer<T>'

Anyone know how to accomplish what I'm attempting here?

Thanks!

Chris

Answer 1

If you make ThingConsumer<T> an interface rather than an abstract class, then your code will work as is.

public interface IThingConsumer<T> where T : IThing
{
    string Name { get; set; }
}

Edit

One more change needed. In ThingConsumerFactory, cast back to the return type IThingConsumer<T>:

return (IThingConsumer<T>)new MyThingConsumer();