title: Can't add element by the button value in angular 5
body: <p>I want to add the button's value to my program.</p>
  
  <p>First I show some buttons.</p>
  
  <pre><code>&lt;button *ngFor="let row of buttonTable.rows" mat-raised-button class="btn btn-sm" value={{row}} (click)="addLab(this.value)"&gt;{{row}}&lt;/button&gt;
  </code></pre>
  
  <p>My addLab() method is </p>
  
  <pre><code>  addLab(value:any):void{
    this.formTable.rows.push([value]);
    }
  </code></pre>
  
  <p>And my buttonTable is like this.</p>
  
  <pre><code>declare interface oneLineTable {
    rows: string[][];
  }
  </code></pre>
  
  <p>But I can't get the value by this click method. Anyone have some ideas?</p>