What is the name of this bad practice / anti-pattern?

Question

I'm trying to explain to my team why this is bad practice, and am looking for an anti-pattern reference to help in my explanation. This is a very large enterprise app, so here's a simple example to illustrate what was implemented:

public void ControlStuff()
    {
        var listOfThings = LoadThings();
        var listOfThingsThatSupportX = new string[] {"ThingA","ThingB", "ThingC"};
        foreach (var thing in listOfThings)
        {
            if(listOfThingsThatSupportX.Contains(thing.Name))
            {
                DoSomething();
            }
        }
    }

I'm suggesting that we add a property to the 'Things' base class to tell us if it supports X, since the Thing subclass will need to implement the functionality in question. Something like this:

public void ControlStuff()
    {
        var listOfThings = LoadThings();
        foreach (var thing in listOfThings)
        {
            if (thing.SupportsX)
            {
                DoSomething();
            }
        }
    }
class ThingBase
{
    public virtual bool SupportsX { get { return false; } }
}
class ThingA : ThingBase
{
    public override bool SupportsX { get { return true; } }
}
class ThingB : ThingBase
{
}

So, it's pretty obvious why the first approach is bad practice, but what's this called? Also, is there a pattern better suited to this problem than the one I'm suggesting?

Answer 1

Normally a better approach (IMHO) would be to use interfaces instead of inheritance

then it is just a matter of checking whether the object has implemented the interface or not.