I'm creating a table that should sort by file name and date I followed the Angular Material documentation for this purpose but is not working, it's not showing any errors in the compiler or the browser console, the table looks like this:

```
<mat-table [dataSource]="dataSource" matSort>
      <ng-container matColumnDef="File">
        <mat-header-cell *matHeaderCellDef mat-sort-header> File </mat-header-cell>
        <mat-cell  *matCellDef="let element" data-label="File"> {{element.fileName}} </mat-cell>
      </ng-container>

      <!-- Name Column -->
      <ng-container matColumnDef="Date">
        <mat-header-cell  *matHeaderCellDef mat-sort-header>Date </mat-header-cell>
        <mat-cell  *matCellDef="let element" data-label="Date"> {{element.date}} </mat-cell>
      </ng-container>
      <!-- Weight Column -->
      <ng-container matColumnDef="Extension">
        <mat-header-cell *matHeaderCellDef mat-sort-header>Extension</mat-header-cell>
        <mat-cell  *matCellDef="let element" data-label="Extension"> {{element.extension}} </mat-cell>
      </ng-container>

      <ng-container matColumnDef="View">
        <mat-header-cell *matHeaderCellDef> Actions </mat-header-cell>
        <mat-cell  *matCellDef="let element" data-label="View"> <a href="{{element.url}}" target="_blank" class="green-text"><i class="material-icons">visibility</i></a></mat-cell>
      </ng-container>

      <ng-container matColumnDef="Delete">
        <mat-header-cell *matHeaderCellDef> Delete </mat-header-cell>
        <mat-cell  *matCellDef="let element" data-label="Delete"> <a class="red-text"><i class="material-icons">delete_forever</i></a></mat-cell>
      </ng-container>
      <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
      <mat-row *matRowDef="let row; columns: displayedColumns;"></mat-row>
    </mat-table>

```

and this is my ts code

```
export class FilesComponent implements OnInit {
  displayedColumns: string[] = ['File', 'Extension', 'Date', 'View', 'Delete'];
  dataSource = new MatTableDataSource<Files>(ELEMENT_DATA);
  data = ELEMENT_DATA;
  selects: any;
  @ViewChild(MatPaginator, {static: true}) paginator: MatPaginator;
  @ViewChild(MatSort, {static: true}) sort: MatSort;
  constructor(private addFile: MatDialog) {
  }

  ngOnInit(): void {
    this.Materialize();
    this.dataSource.paginator = this.paginator;
    this.dataSource.sort = this.sort;
  }

  Materialize() {
    this.selects = document.querySelectorAll('select');
    M.FormSelect.init(this.selects);
  }

  changeFiles(value) {
    console.log('option:', value);
    switch (parseInt(value)) {
      case 1:
        this.dataSource = new MatTableDataSource<Files>(ELEMENT_DATA);
        break;
      case 2:
        this.dataSource = new MatTableDataSource<Files>(Charts);
        break;
      case 3:
        this.dataSource = new MatTableDataSource<Files>(Documents);
        break;
      default:
        this.dataSource = new MatTableDataSource<Files>(ELEMENT_DATA);
        break;
    }
    this.dataSource.sort = this.sort;
    this.dataSource.paginator = this.paginator;
  }
}

```

event the sort header it's applied and the styles (the arrows for the sort) appear in the table the data does not sort.