高手进来，vb.net的generic问题请教！

            // ...
            dispatchcallback callbackthunk = delegate（tlhs lhs, trhs rhs)
            {
                return callback（（tconcretelhs)lhs, （tconcreterhs)rhs);
            };
            // ...

'...
dim foo as new foo（of tconcretelhs, tconcreterhs)
foo.callback = callback
dim callbackthunk as dispatchcallback = new dispatchcallback（addressof foo.bar)
'...
private class foo（of tconcretelhs as tlhs, tconcreterhs as trhs)
   public callback as dispatchcallback（of tconcretelhs, tconcreterhs)
   public function bar（lhs as tlhs, rhs as trhs) as treturn
      return callback（directcast（lhs, tconcretelhs), directcast（rhs, tconcreterhs))
   end function
end class