How do I change the ionselect option while I use the slide?

[NetGospel]

Hello, I recently started using Ionic and I’m building an app. In this app I’m doing I need to change the ionselect when I use the slide. I am trying in many ways but I can’t find a way to do that.

Here is my code:
HTML:

<ion-header>

  <ion-toolbar color="primary">

    <ion-buttons slot="start">

      <ion-menu-button></ion-menu-button>

    </ion-buttons>

    <ion-title style="text-align: center;"> Estudos de Libertação </ion-title>

  </ion-toolbar>

</ion-header>

<ion-content>

  <ion-item>

    <ion-select placeholder="0" [(ngModel)]="PAGINA_SELECIONADA" (ionChange)="OnChange($event)" interface="popover">

      <ion-select-option value="0">Introdução</ion-select-option>

      <ion-select-option value="1">1</ion-select-option>

      <ion-select-option value="2">2</ion-select-option>

      <ion-select-option value="3">3</ion-select-option>

      <ion-select-option value="4">4</ion-select-option>

      <ion-select-option value="5">5</ion-select-option>

      <ion-select-option value="6">6</ion-select-option>

      <ion-select-option value="7">7</ion-select-option>

      <ion-select-option value="8">8</ion-select-option>

      <ion-select-option value="9">9</ion-select-option>

      <ion-select-option value="10">10</ion-select-option>

      <ion-select-option value="11">11</ion-select-option>

      <ion-select-option value="12">12</ion-select-option>

      <ion-select-option value="13">13</ion-select-option>

      <ion-select-option value="14">14</ion-select-option>

      <ion-select-option value="15">15</ion-select-option>

      <ion-select-option value="16">16</ion-select-option>

      <ion-select-option value="17">17</ion-select-option>

      <ion-select-option value="18">18</ion-select-option>

      <ion-select-option value="19">19</ion-select-option>

      <ion-select-option value="19">19</ion-select-option>

      <ion-select-option value="20">20</ion-select-option>

      <ion-select-option value="21">21</ion-select-option>

      <ion-select-option value="22">22</ion-select-option>

      <ion-select-option value="23">23</ion-select-option>

      <ion-select-option value="24">24</ion-select-option>

      <ion-select-option value="25">25</ion-select-option>

      <ion-select-option value="26">26</ion-select-option>

      <ion-select-option value="27">27</ion-select-option>

      <ion-select-option value="26">26</ion-select-option>

      <ion-select-option value="27">27</ion-select-option>

      <ion-select-option value="28">28</ion-select-option>

      <ion-select-option value="29">29</ion-select-option>

      <ion-select-option value="30">30</ion-select-option>

      <ion-select-option value="31">31</ion-select-option>

      <ion-select-option value="32">32</ion-select-option>

      <ion-select-option value="33">33</ion-select-option>

      <ion-select-option value="34">34</ion-select-option>

      <ion-select-option value="35">35</ion-select-option>

      <ion-select-option value="36">36</ion-select-option>

      <ion-select-option value="37">37</ion-select-option>

      <ion-select-option value="38">38</ion-select-option>

      <ion-select-option value="39">39</ion-select-option>

      <ion-select-option value="40">40</ion-select-option>

      <ion-select-option value="41">42</ion-select-option>

      <ion-select-option value="43">43</ion-select-option>

      <ion-select-option value="44">44</ion-select-option>

      <ion-select-option value="45">45</ion-select-option>

      <ion-select-option value="46">46</ion-select-option>

      <ion-select-option value="47">47</ion-select-option>

      <ion-select-option value="48">48</ion-select-option>

      <ion-select-option value="49">49</ion-select-option>

      <ion-select-option value="50">50</ion-select-option>

      <ion-select-option value="51">51</ion-select-option>

      <ion-select-option value="52">52</ion-select-option>

      <ion-select-option value="53">53</ion-select-option>

      <ion-select-option value="54">54</ion-select-option>

      <ion-select-option value="55">55</ion-select-option>

      <ion-select-option value="56">56</ion-select-option>

      <ion-select-option value="57">57</ion-select-option>

      <ion-select-option value="58">58</ion-select-option>

      <ion-select-option value="59">59</ion-select-option>

      <ion-select-option value="60">60</ion-select-option>

      <ion-select-option value="61">61</ion-select-option>

      <ion-select-option value="62">62</ion-select-option>

      <ion-select-option value="63">63</ion-select-option>

      <ion-select-option value="64">64</ion-select-option>

      <ion-select-option value="65">65</ion-select-option>

      <ion-select-option value="66">66</ion-select-option>

      <ion-select-option value="67">67</ion-select-option>

      <ion-select-option value="68">68</ion-select-option>

      <ion-select-option value="69">69</ion-select-option>

      <ion-select-option value="70">70</ion-select-option>

      <ion-select-option value="71">71</ion-select-option>

      <ion-select-option value="72">72</ion-select-option>

      <ion-select-option value="73">73</ion-select-option>

      <ion-select-option value="74">74</ion-select-option>

      <ion-select-option value="75">75</ion-select-option>

      <ion-select-option value="76">76</ion-select-option>

      <ion-select-option value="77">77</ion-select-option>

      <ion-select-option value="78">78</ion-select-option>

      <ion-select-option value="79">79</ion-select-option>

      <ion-select-option value="80">80</ion-select-option>

      <ion-select-option value="81">81</ion-select-option>

      <ion-select-option value="82">82</ion-select-option>

      <ion-select-option value="83">83</ion-select-option>

      <ion-select-option value="84">84</ion-select-option>

      <ion-select-option value="85">85</ion-select-option>

      <ion-select-option value="86">86</ion-select-option>

      <ion-select-option value="87">87</ion-select-option>

      <ion-select-option value="88">88</ion-select-option>

      <ion-select-option value="89">89</ion-select-option>

      <ion-select-option value="90">90</ion-select-option>

      <ion-select-option value="91">91</ion-select-option>

      <ion-select-option value="92">92</ion-select-option>

      <ion-select-option value="93">93</ion-select-option>

      <ion-select-option value="94">94</ion-select-option>

      <ion-select-option value="95">95</ion-select-option>

      <ion-select-option value="96">96</ion-select-option>

      <ion-select-option value="97">97</ion-select-option>

      <ion-select-option value="98">98</ion-select-option>

      <ion-select-option value="99">99</ion-select-option>

      <ion-select-option value="100">100</ion-select-option>

      <ion-select-option value="101">101</ion-select-option>

    </ion-select>

    <ion-label class="ion-hide">Selecione a página</ion-label>

    <ion-button slot="end">

    <ion-icon name="volume-medium-outline"></ion-icon></ion-button>

  </ion-item>

  <ion-slides #slider  (ionSlideDidChange)="slideChanged()">

    <ion-slide>

      Slide Introdução

    </ion-slide>

    <ion-slide>

      Slide 1

    </ion-slide>

    <ion-slide>

      Slide 2

    </ion-slide>

    <ion-slide>

      Slide 3

    </ion-slide>

    <ion-slide>

      Slide 4

    </ion-slide>

    <ion-slide>

      Slide 5

    </ion-slide>

    <ion-slide>

      Slide 6

    </ion-slide>

    <ion-slide>

      Slide 7

    </ion-slide>

    <ion-slide>

      Slide 8

    </ion-slide>

    <ion-slide>

      Slide 9

    </ion-slide>

    <ion-slide>

      Slide 10

    </ion-slide>

    <ion-slide>

      Slide 11

    </ion-slide>

    <ion-slide>

      Slide 12

    </ion-slide>

    <ion-slide>

      Slide 13

    </ion-slide>

    <ion-slide>

      Slide 14

    </ion-slide>
</ion-content>

TS:

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { AppComponent } from './../app.component';
import { Component, ElementRef, OnInit, ViewChild } from '@angular/core';
import {IonSlides, Platform} from '@ionic/angular';
import { ThrowStmt } from '@angular/compiler';
import { EventEmitter } from 'events';
import { eventNames } from 'process';


@Component({
  selector: 'app-libertacao',
  templateUrl: './libertacao.page.html',
  styleUrls: ['./libertacao.page.scss'],
})
export class LibertacaoPage implements OnInit {
  @ViewChild(IonSlides) slides: IonSlides;
  PAGINA_SELECIONADA: number;
  // tslint:disable-next-line: variable-name
  index_atual: number;
  booleano: boolean;
  constructor(){
  }
  ngOnInit(){
  }
  OnChange(event: any)
  {
    /*if (event.detail.value === this.PAGINA_SELECIONADA) {
      this.slides.slideTo(this.PAGINA_SELECIONADA);
    }*/
    if (event.detail.value !== this.index_atual){
      // tslint:disable-next-line: no-unused-expression
      event.detail.value === this.index_atual;
    }
    else {}
    console.log(event.detail.value);
    console.log(this.index_atual);

  }

  slideChanged() {
    this.slides.getActiveIndex().then((index) => {
       this.index_atual = index;
    });
    }

}