Parameter passing / call between Vue assembly

Not directly invoke methods or parameter passing between the components Sons

Parent => promoter, by value (props)
using v-bind to the traditional values subassembly, the subassembly is received props used
in the process should be directly used this.yingfu, but I did not succeed

father:

child:

Sub => parent, traditional values ​​( $EMIT) used in the method of subassembly$ emit method to trigger a password parent element binding
Note html not case-sensitive password supposedly declared hideCoupon subassembly within parent components bound to html you can use hide-coupon, but did not trigger
the father:


son:

Sub => parent, call ( $refs) parent component to define a method, in which by then$ refs subassembly to call the corresponding methods
Parent:

child: