How to get child class Type and members from parent class?

[zoujiaqing]

import std.stdio;


class A
{
     this(T)(T t)
     {

     }

     void write()
     {
         T _this = cast(T) this;
         writeln(this.v);
     }
}

class B : A
{
     string v = "hello";
}

void main()
{
     auto b = new B;

     writeln(b.write()); // print hello
}