title: How to programmatically expand a mat-expansion-panel, which was added dynamically?
body: <p>I am trying to display multiple Mat-expansion-panel within a Mat-accordian by using *ngFor. I need to add a new mat-expansion-panel on click of a button which i am able to do. I am also required to expand (open) this newly added expansion panel on click of the button, and this is what i have been unable to achieve. Please help.</p>
  
  <p>Stackblitz - <a href="https://stackblitz.com/edit/angular-fh5vu1-g6phe6?file=app%2Fexpansion-steps-example.ts" rel="noreferrer">https://stackblitz.com/edit/angular-fh5vu1-g6phe6?file=app%2Fexpansion-steps-example.ts</a></p>
  
  <pre><code>export class ExpansionStepsExample { 
    items: number[] = [1,2,3];
  
    AddNewRow() {
      this.items.push(4);
    }
  }
  </code></pre>
  
  <pre><code>&lt;mat-accordion class="example-headers-align"&gt;
    &lt;mat-expansion-panel *ngFor="let item of items;"&gt;
      &lt;mat-expansion-panel-header&gt;
        &lt;mat-panel-title&gt; {{item}} &lt;/mat-panel-title&gt;
      &lt;/mat-expansion-panel-header&gt;
      {{item}}
    &lt;/mat-expansion-panel&gt;
  &lt;/mat-accordion&gt;
  &lt;button (click)="AddNewRow()" value="Add New"&gt; Add New &lt;/button&gt;
  </code></pre>