c# - Get all last descendants of a base type? -

this question opposite of how find types direct descendants of base class?

if inheritance hierarchy have,

class base {  }    class derived1 : base {  }  class derived1a : derived1 {  }  class derived1b : derived1 {  }    class derived2 : base {  } 

i need mechanism find sub types of base class in particular assembly @ end of inheritance tree. in other words,

subtypesof(typeof(base))  

should give me

-> { derived1a, derived1b, derived2 } 

this have come with. not sure if more elegant/efficient solutions exist..

public static ienumerable<type> getlastdescendants(this type t) {     if (!t.isclass)         throw new exception(t + " not class");      var subtypes = t.assembly.gettypes().where(x => x.issubclassof(t)).toarray();     return subtypes.where(x => subtypes.all(y => y.basetype != x)); } 

and sake of completeness, repost answer direct descendants given here

public static ienumerable<type> getdirectdescendants(this type t) {     if (!t.isclass)         throw new exception(t + " not class");      return t.assembly.gettypes().where(x => x.basetype == t); }