角度材料数据表没有排序？

Question

[STACKBLITS LINK] I'm attempting a minimal angular material data table with sorting .

I've added the MatSortModule, implemented @ViewChild in the class, added the directives, set the dataSource.sort property etc. and I get the arrow on the table when I mouse hover, but the data does not sort.

Thoughts?

    import { Component, OnInit, ViewChild } from '@angular/core';
    import { MatTableDataSource, MatSort } from "@angular/material";

    class Todo {
      id: string;
      description: string;
      complete: boolean;
    }
    @Component({
      selector: 'my-app',
      templateUrl: './app.component.html',
      styleUrls: ['./app.component.css']
    })
    export class AppComponent implements OnInit {
      @ViewChild(MatSort, {static: false}) sort: MatSort;

      /**
      * Control column ordering and which columns are displayed.
      */
      displayedColumns:string[] =  ['id'];
      dataSource: MatTableDataSource<Todo>;

      ngOnInit() {
        const todos: Todo[] = [
          { id: '123', description: 'Complete me!', complete: false },
          { id: '321', description: 'You Completed me!', complete: true }];
        this.dataSource = new MatTableDataSource(todos);
        this.dataSource.sort = this.sort;
      }
    }


    <mat-table class="mat-elevation-z8" [dataSource]="dataSource" matSort>
      <ng-container matColumnDef="id">
        <mat-header-cell *matHeaderCellDef mat-sort-header>ID</mat-header-cell>
        <mat-cell *matCellDef="let row;">{{row.id}}</mat-cell>
      </ng-container>
      <mat-header-row *matHeaderRowDef="displayedColumns">
      </mat-header-row>
      <mat-row *matRowDef="let row; columns: displayedColumns"></mat-row>
    </mat-table>

Answer 1

The ViewChild for MatSort is undefined at ngOnInit since the view has not yet been initialized. To resolve this, set the MatSort on your dataSource after the view has initialized by using the ngAfterViewInit lifecycle hook.

ngAfterViewInit() {
    this.dataSource.sort = this.sort;
}

Answer 2

I had the same issue, you need to set the MatSort. This is how I fixed it

@ViewChild(MatSort, {static: false}) set  sortMeeting (ms: MatSort){
this._sort = ms;
this.renewDataSource(); }

............................................

ngOnInit(){
this.dataSource = new MatTableDataSource(todos);
this.renewDataSource();
}


renewDataSource() {
this.dataSource.sort = this._sort;
}

I hope it helps. :)