It's very kind of you to …. 「・・・して下さってどうもご親切様です」toのあとに give up your seat for me(席を譲って頂いて)、とか to take all the trouble for me(面倒なこと引き受けて頂いて)など、親切でやってもらったことを言おう。
「ご親切に」の代わりに「賢いですね」、「馬ッ鹿だねェ」など、応用は広い。おのおの、
It's very wise of you to ….
It's very stupid of you to ….
It's very stupid of you to spill the beans before him.