Retrieve the most recent data selected from a dropdown menu upon clicking the back button while utilizing Angular15

I am new to Angular and could really use some assistance with a problem I'm facing.

Situation: I'm currently working on angular15 and have implemented a dropdown list. When selecting an option from the first dropdown, it populates values in the second dropdown automatically. Once the second dropdown is selected, I need to click on a submit button to navigate to the next page.

Issue: The problem arises when I navigate to the next page and then want to go back to view the previously selected options. How can I achieve this?

What method should I use to retrieve the selected options?

I attempted using the router method, but it doesn't seem to be working.

A.component.html

First Dropdown:

<select #selectField class="form-select" 
                  (change)="setFieldValues(selectField.value, i)">
                  <option selected value="null" style="display: none;"> please-select</option>                     
                  <ng-container *ngFor="let field of dataFields">                        
                    <option value="{{field.name}}">{{field.name}}</option>
                  </ng-container>
                </select>

Second Dropdown:

<select #selectSecond class="form-select"
                      (change)="setInputsWidth(selectSecond.value, i)">
                      <option selected value="null" style="display: none;" >please-select</option>                      
                      <ng-container *ngFor="let operand of getSecond(selectField.value)">                       
                        <option value="{{operand}}"> operand</option>
                      </ng-container>
                    </select>

B.component.html

<button (click)="backToPageA()">Back</button>

B.component.ts

backToPageA(){
  this.router.navigate(["/PageA"]);
}

Answer №1

Utilize a service to securely store values within your application without the risk of them being destroyed.

import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root'
})
export class DataService {
  private myData: any;

  setData(data: any) {
    this.myData = data;
  }

  getData() {
    return this.myData;
  }
}

It is important to keep in mind that the stored values will persist indefinitely, potentially affecting future selections. Be sure to implement logic to handle previous route scenarios and prevent unintended changes in select boxes.

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