<ion-content>
<div class="dashboardSection">

            <a href="" (click)="fetchAllClass()">
                <div class="header padding text-center classes common">
                    <img src="assets/images/icos_15.png" alt="Your logo here"  width="50%" height="auto"/>
                    <p class="Sectiontitle">STUDENTS</p>
                </div>
            </a></div>
</ion-content>

doLogin(event) {
    var user1 =this.loginForm.value;
    var password = this.loginForm.controls.password.value;
    this.homeService.doLogin(user1).subscribe(
        user =>{
            this.user = user.results;
            this.storage.set('isLoggedIn', 'shahjad');
            this.navCtrl.setRoot(DashboardComponent, {thing1: user });
        },
        err => {
            console.log(err);
        },
        () => console.log('login complete')

        );
}

@Component({

    selector: 'page-students',
    templateUrl: "./students.html"
})
export class StudentsComponent {
    dashboardItem: any;
    mode = "Observable";
    errorMessage: string;

    constructor(public fb: FormBuilder,private studentsService: StudentsService,public navCtrl: NavController,private storage: Storage,private menu: MenuController) {}

    fetchAllClass(event) {

        alert("fd");
    }
}

<page-student #student></page-student>

@ViewChild('student') student: StudentComponent

import { Component,Inject,forwardRef } from '@angular/core';
import {StudentComponent} from '../component/students'
@Component({
   selector: 'dashboard',
   templateUrl: 'dashboard.html',
   providers:[StudentComponent]
})
constructor(@Inject(forwardRef(() => StudentComponent))private studentComponent: StudentComponent){
}

fetchAllClass(event) {
this.studentComponent.fetchAllClass(event);
}

<a href="" (click)="fetchAllClass()">