because when you are using interfaces you can check whether the component is
type of that interface. if it is then you can simply type cast it and call
any method you have defined in interface knowing that it wont crash at
but in accessing through parent you dont have this control... your
application can crash at runtime if you call some non existing function.
query string a bit too cumbersome to do and if you change something in the
component you have to make changes in every place.
-> Akshar Kaul <-