angular5 material can't show any data in table - angular-material

Question

Here is my angular project configuration,
"#angular/cdk": "^5.2.0",
"#angular/common": "~5.2.6",
"#angular/compiler": "~5.2.6",
"#angular/core": "~5.2.6",
"#angular/forms": "~5.2.6",
"#angular/http": "~5.2.6",
"#angular/material": "^5.2.0"
I am using angular material to build a table of data, I am following the https://material.angular.io/components/table/examples example, the code is almost the same with the exmaple, but the table just doesn't show any thing.
Here is the code:
ts code
export class ordersComponent {
displayedColumns =['position', 'name', 'weight', 'symbol'];
//dataSource = new MatTableDataSource<PeriodicElement>(ELEMENT_DATA);
dataSource = ELEMENT_DATA;
}
export interface PeriodicElement {
name: string;
position: number;
weight: number;
symbol: string;
}
const ELEMENT_DATA : PeriodicElement[]= [
{position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H'},
{position: 2, name: 'Helium', weight: 4.0026, symbol: 'He'},
{position: 3, name: 'Li: PeriodicElement[]thium', weight: 6.941, symbol: 'Li'},
{position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be'}
];
The html code is
<div class="mat-elevation-z8">
<mat-table mat-table [dataSource]="dataSource">
<ng-container matColumnDef="position">
<th mat-header-cell *matHeaderCellDef> No. </th>
<td mat-cell *matCellDef="let element"> </td>
</ng-container>
<ng-container matColumnDef="name">
<th mat-header-cell *matHeaderCellDef> Name </th>
<td mat-cell *matCellDef="let element"> </td>
</ng-container>
<ng-container matColumnDef="weight">
<th mat-header-cell *matHeaderCellDef> Weight </th>
<td mat-cell *matCellDef="let element"> </td>
</ng-container>
<ng-container matColumnDef="symbol">
<th mat-header-cell *matHeaderCellDef> Symbol </th>
<td mat-cell *matCellDef="let element"> {{element.symbol}} </td>
</ng-container>
<tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
<tr mat-row *matRowDef="let row; columns: displayedColumns;"></tr>
</mat-table>
</div>
I have looked into the html, found the html has produced 4 exact table html elements, but why it just doens't show any data on each html element?

Answer 1

Don't go with complicated solution. Instead of that create a instance of "MatTableDataSource" and in MatTableDataSource having 'data' is the property so, you can directly assign the array to this.
I added a demo here stackblitz