Auto refresh a child component after submit in the same page

I would like to know if you could to tell how to refresh a child component after submit in the same page…???

This is my code:

comment page HTML:

  Generated template for the CommentPage page.

  See for more info on
  Ionic pages and navigation.



<ion-content no-padding>
   <app-commentview  [(comment)]="commentDatas"></app-commentview>


    <form [formGroup]="commentForm" (ngSubmit)="saveComment()">
      <ion-col col-9>
          <ion-textarea name="commenttxt" formControlName="commenttxt" placeholder="comment here..."></ion-textarea>
      <ion-col col-3>
          <button ion-button clear type="submit">Submit</button>

Comment page TS:

import { Component, OnInit } from '@angular/core';
import { IonicPage, NavController, NavParams } from 'ionic-angular';

//import { Comments } from "../../models/comments/comments.interface";
import "rxjs/add/operator/map";
import { Http, Headers } from '@angular/http';
import { FormBuilder, Validators } from '@angular/forms';

  selector: 'page-comment-page',
  templateUrl: 'comment-page.html',
export class CommentPage  implements OnInit {
  comments: string;


  constructor( private http: Http, private navCtrl: NavController, private navParams: NavParams, public _form: FormBuilder) {


ngOnInit() {
  this.commentForm ={

//this.comments = "exemplestring";

   this.postID = this.navParams.get('idcomment');

let headers = new Headers();

    this.http.get('http://localhost:9000/hsc/api/comments?post_id='+ this.postID, {headers: headers, withCredentials: true})
  .map(res => res.json())
  .subscribe(data => {
       this.commentDatas = data.results;


    let headers = new Headers();
    let postmsg = {
      "text": this.commentForm.value.commenttxt, 
      "post_id": this.postID
    };'http://localhost:9000/hsc/api/comments', postmsg ,{headers: headers, withCredentials: true})
    .subscribe(data => {
        console.log("COMMENT ADDED", postmsg);
      }, error => {
        console.log(error);// Error getting the data


commentview-component HTML:

<div *ngFor="let c of commentData">
    <ion-col align-self-center>
     <ion-item class="clh6">
    <ion-avatar item-left>
      <img src="assets/images/avatar.png">
    <h6 >{{c.first_name}} {{c.last_name}}</h6>
       <ion-col text-right align-self-center padding-right>
        <ion-note>{{ c.date_added | amTimeAgo }}</ion-note>
    <ion-row class="commsg">

commentview-component TS:

import { Component, Input } from '@angular/core';
import { NavController, NavParams } from 'ionic-angular';

 * Generated class for the Commentview component.
 * See
 * for more info on Angular Components.
  selector: 'app-commentview',
  templateUrl: 'commentview.component.html'

export class CommentviewComponent {
@Input("comment") _comment;


  constructor( private navCtrl: NavController, private navParams: NavParams) {

ngAfterViewInit() {
     this.commentData= this._comment;

     console.log("COMMENTVIEW:", this.commentData);



thanks in advance ad your help will be aprreciated!