Angular ngFor无法使用材质，因为它不是已知属性

Question

angular ngfor can't bind to 'ngForOf' since it isn't a known property of

  <div class="col-md-3 col-sm-3 shadow-sm bg-white rounded leftSideBar">
            <ul class="list-group">
                <mat-radio-group aria-label="Select an option">
                    <li class="list-group-item" *ngFor="let item of items">
                        {{i.name}}
                        <mat-radio-button [value]="i.id"></mat-radio-button>
                    </li>
                </mat-radio-group>
            </ul>
        </div>

Answer 1

Add BrowserModule to imports: [] in AppModule

import { BrowserModule } from '@angular/common';
..
..
@NgModule({
  imports: [ BrowserModule ],
  ..
})