title: how to use scroll event in angular material mat select?
body: <p>i have a large list and i want to load it as the user scroll down the select field but how can i get the scroll event in mat-select there is no event that fire the scroll event. </p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;mat-form-field&gt;
    &lt;mat-select placeholder="Choose a Doctor" formControlName="selectedDoc" (change)="drSelected()"&gt;
      &lt;div *ngFor="let dr of doctors;let i = index" [matTooltip]="getDocDetail(i)" matTooltipPosition="right"&gt;
        &lt;mat-option (scroll)="docScroll()" [value]="dr"&gt;
          {{dr.name}}
        &lt;/mat-option&gt;
      &lt;/div&gt;
    &lt;/mat-select&gt;
    &lt;mat-hint&gt;List Of Doctor In Your city&lt;/mat-hint&gt;
    &lt;mat-error *ngIf="selectedDoc.hasError('required')"&gt;Please Select A Dr&lt;/mat-error&gt;
  &lt;/mat-form-field&gt;
  </code></pre>
  
  <p>(scroll) don't work because mat-select don't have any scroll event any other way i can achieve this i want to show like 10 item first then populate the rest item when user scroll end of the options .</p>