How to get Type[] of all classes a class extends

Question

You can do Type[] interfaces = typeof(MyClass).GetInterfaces(); to get a list of everything a class implements implements.

I am wondering if there is anyway to crawl the "extends" tree to see all the base types a class inherits, i.e. abstract classes etc.?

Answer 1

You can use Type.BaseType to traverse from the top-level type to the most base type until the base type reaches object.

Something like this:

abstract class A { }
class B : A { }
class C : B { }

public static void Main(string[] args)
{
    var target = typeof(C);

    var baseTypeNames = GetBaseTypes(target).Select(t => t.Name).ToArray();

    Console.WriteLine(String.Join(" : ", baseTypeNames));
}

private static IEnumerable<Type> GetBaseTypes(Type target)
{
    do
    {
        yield return target.BaseType;

        target = target.BaseType;
    } while (target != typeof(object));
}

Answer 2

I use this code to get all classes that inherits a defined Type. It searches all loaded Assemblies. Usefull if you have only the Baseclass and you will get all Classes that Extends the Baseclass.

Type[] GetTypes(Type itemType) {
    List<Type> tList = new List<Type>();
    Assembly[] appAssemblies = AppDomain.CurrentDomain.GetAssemblies();
    foreach (Assembly a in appAssemblies) {
        Module[] mod = a.GetModules();
        foreach (Module m in mod) {
            Type[] types = m.GetTypes();
            foreach (Type t in types) {
                try {
                    if (t == itemType || t.IsSubclassOf(itemType)) {
                        tList.Add(t);
                    }
                }
                catch (NullReferenceException) { }
            }
        }
    }
    return tList.ToArray();
}