Angular matSort not working

Question

I am having problems importing matSort into my matTable.

I provide you my code:

dashboard.component.ts

import {Component, ViewChild} from '@angular/core';
import {UserService} from "../user.service";
import {DohvatMantisaService} from "../dohvat-mantisa.service";
import {Mantisi} from "../Mantisi";
import {Observable} from "rxjs/Observable";
import {DataSource} from "@angular/cdk/collections";
import 'rxjs/add/observable/of';
import 'rxjs/add/operator/startWith';
import 'rxjs/add/observable/merge';
import {MatSort} from '@angular/material';
@Component({
  selector: 'app-dashboard',
  templateUrl: './dashboard.component.html',
  styleUrls: ['./dashboard.component.css']
})
export class DashboardComponent{
  displayedColumns = ['projekt', 'manits', 'kategorija','ozbiljnost','datum_prijave','postavio','odjel','postavio','naziv','status','planirana_isporuka'];
  constructor(private user:UserService, private dohvatMantisa:DohvatMantisaService) {
  }
  dataSource: TableDataSource | null;
  mantisi: Mantisi[];
  name = this.user.getUsername();
  @ViewChild(MatSort) sort: MatSort;
  ngOnInit() {
    this.dataSource = new TableDataSource(this.dohvatMantisa,this.sort);
  }
}

export class TableDataSource extends DataSource<Mantisi>{
  constructor(private mantisiDS: DohvatMantisaService,private sort: MatSort){
    super();
  }
  connect(): Observable<Mantisi[]> {
    const displayDataChanges = [
      this.mantisiDS.dohvatiMantise(),
      this.sort.sortChange,
    ];

    return Observable.merge(...displayDataChanges).map(() => {
      return this.getSortedData();
    });
  }
  disconnect() {}

  getSortedData(): Mantisi[]{
    const data = this.mantisiDS.prikazMantisa().slice();
    if (!this.sort.active || this.sort.direction == '') { return data; }
    return data.sort((a, b) => {
      let propertyA: number|string = '';
      let propertyB: number|string = '';
      switch (this.sort.active) {
        case 'projekt': [propertyA, propertyB] = [a.projekt, b.projekt]; break;
        case 'manits': [propertyA, propertyB] = [a.manits, b.manits]; break;
        case 'kategorija': [propertyA, propertyB] = [a.kategorija, b.kategorija]; break;
        case 'ozbiljnost': [propertyA, propertyB] = [a.ozbiljnost, b.ozbiljnost]; break;
        case 'datum_prijave': [propertyA, propertyB] = [a.datum_prijave, b.datum_prijave]; break;
        case 'postavio': [propertyA, propertyB] = [a.postavio, b.postavio]; break;
        case 'naziv': [propertyA, propertyB] = [a.naziv, b.naziv]; break;
        case 'status': [propertyA, propertyB] = [a.status, b.status]; break;
        case 'planirana_isporuka': [propertyA, propertyB] = [a.planirana_isporuka, b.planirana_isporuka]; break;
      }

      let valueA = isNaN(+propertyA) ? propertyA : +propertyA;
      let valueB = isNaN(+propertyB) ? propertyB : +propertyB;

      return (valueA < valueB ? -1 : 1) * (this.sort.direction == 'asc' ? 1 : -1);
    });
  }
}

This is my service: dohvatMantisaService

import { Injectable } from '@angular/core';
import {Http, Response, RequestOptions, Headers} from "@angular/http";
import {Observable} from "rxjs/Observable";
import {Mantisi} from "./Mantisi";
import 'rxjs';
import 'rxjs/operator/map';
import 'rxjs/operator/do';

@Injectable()
export class DohvatMantisaService {
  constructor(public http:Http) { }
  result: Mantisi[];
  dohvatiMantise(): Observable<Mantisi[]>{
    return this.http.get('/mantis/getMantisReport').map(this.extractData);
  }
  private extractData(response: Response) {
    let body = response.json();
    return body || {};
  }

  prikazMantisa(): Mantisi[]{
    this.dohvatiMantise().subscribe(res => this.result = res);
    return this.result;
  }
}

And im giving you the dashboard.component.html matSort line:

<mat-table #table [dataSource]="dataSource" class="example-table" matSort>

The main problem is that the data is being downloaded and received from an HTTP request, but I get errors in the console, for example:

Unable to read sortChange property from undefined in TableDataSource.webpackJsonp ... / .. / .. / .. / .. / src / app / dashboard / dashboard.component.ts.TableDataSource.connect (dashboard.component.ts: 36) in MatTable.webpackJsonp ... / .. / .. / cdk / esm5 / table.es5.js.CdkTable._observeRenderChanges (table.es5.js: 602) in MatTable.webpackJsonp ... / .. / .. / cdk / esm5 / table.es5.js.CdkTable.ngAfterContentChecked (table.es5.js: 522)

, this.sort.sortChange undefined. . , .

Answer 1

.

, . dataSource. . http.get .

.

fetchData(id){
  this.fetch.getProcesses(id).subscribe(result => {
    this.processes = result;
    this.dataSource = new TableDataSource(this.processes);
    Observable.fromEvent(this.filter.nativeElement, 'keyup')
      .debounceTime(150)
      .distinctUntilChanged()
      .subscribe(() => {
        if (!this.dataSource) {
          return;
        }
        this.dataSource.filter = this.filter.nativeElement.value;
      });
  });
}




export class TableDataSource extends DataSource<Proces>{
  _filterChange = new BehaviorSubject('');
  get filter(): string {
    return this._filterChange.value;
  }
  set filter(filter: string) {
    this._filterChange.next(filter);
  }
  filteredData: any =[];

  constructor(private processes:Proces[]){
    super();
  }
  connect(): Observable<Proces[]>{
    const displayDataChanges = [
      this.processes,
      this._filterChange,
    ];
    return Observable.merge(...displayDataChanges).map(() => {
      this.filteredData = this.processes.slice().filter((item: Proces) => {
        const searchStr = (item.name).toLowerCase();
        return searchStr.indexOf(this.filter.toLowerCase()) !== -1;

      });
      return this.filteredData;
    })
  }
  disconnect(){}
}



      <div class="header">
    <mat-form-field floatPlaceholder="never">
      <input matInput #filter placeholder="Pretraži procese">
    </mat-form-field>
  </div>
  <mat-table #table [dataSource]="dataSource" class="table-mantis" matSort>

    <ng-container matColumnDef="col1">
      <mat-header-cell *matHeaderCellDef class="table-header-cell" mat-sort-header> Name</mat-header-cell>
      <mat-cell *matCellDef="let row" class="example-cell" > {{row.nazivProcesa}} </mat-cell>
    </ng-container>

    <ng-container matColumnDef="col2">
      <mat-header-cell *matHeaderCellDef class="table-header-cell" mat-sort-header> Cell 2</mat-header-cell>
      <mat-cell *matCellDef="let row" class="example-cell" > {{row.nazivVlasnika
        }} </mat-cell>
    </ng-container>

    <ng-container matColumnDef="col3">
      <mat-header-cell *matHeaderCellDef class="table-header-cell" mat-sort-header> Cell 3</mat-header-cell>
      <mat-cell *matCellDef="let row" class="example-cell" > {{row.interniAkt}} </mat-cell>
    </ng-container>

    <mat-header-row *matHeaderRowDef="displayedColumns" class="example-header-row"></mat-header-row>
    <mat-row class="example-row" *matRowDef="let row; columns: displayedColumns;"></mat-row>
  </mat-table>

Answer 2

"* ngIf" , viewchield undefined.

Answer 3

, , , , matSort viewChild , MatSortModule module.ts .

: @NgModule({ imports: [ MatSortModule, MatTableModule, ] )}

Answer 4

, , :

@ViewChild(MatSort) set matSort(ms: MatSort) {
this.sort = ms;
this.setDataSourceAttributes();
 }

@ViewChild(MatPaginator) set matPaginator(mp: MatPaginator) {
 this.paginator = mp;
this.setDataSourceAttributes();
 }

setDataSourceAttributes() {
  this.dataSource.paginator = this.paginator;
  this.dataSource.sort = this.sort;
  }

Answer 5

.

, OnInit, . , (), , .

:

<div class="card">

    <div class="card-header">
      <h4>{{pageTitle}}</h4>
      <mat-form-field>
        <input matInput (keyup)="applyFilter($event.target.value)" placeholder="Filter">
      </mat-form-field>
    </div>

    <div class="card-body p-0">    
      <div class="mat-elevation-z8">
        <table mat-table [dataSource]="dataSource" matSort>

          <ng-container matColumnDef="projectNumber">
            <th mat-header-cell *matHeaderCellDef mat-sort-header> Werf Nummer </th>
            <td mat-cell *matCellDef="let row"> W{{row.projectNumber}} </td>
          </ng-container>

          <ng-container matColumnDef="description">
            <th mat-header-cell *matHeaderCellDef mat-sort-header> Omschrijving </th>
            <td mat-cell *matCellDef="let row"> {{row.description}} </td>
          </ng-container>

          <tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
          <tr mat-row *matRowDef="let row; columns: displayedColumns;">
          </tr>
        </table>

        <mat-paginator [pageSizeOptions]="[10,20,100]"></mat-paginator>
      </div>      
    </div>
  </div>

angular

    export class ProjectListComponent {
      pageTitle = 'Projects';
      displayedColumns: string[] = ['projectNumber', 'description'];
      dataSource: MatTableDataSource<Project>;

      @ViewChild(MatPaginator, {static: true}) paginator: MatPaginator;
      @ViewChild(MatSort, {static: true}) sort: MatSort;
      @Input() set projects(value: Project[]){
        this.dataSource = new MatTableDataSource(value);
        this.dataSource.paginator = this.paginator;
        this.dataSource.sort = this.sort;
      }
      @Input() selectedProject: Project;
      @Output() selected = new EventEmitter<Project>();

      applyFilter(filterValue: string) {
        this.dataSource.filter = filterValue.trim().toLowerCase();

        if (this.dataSource.paginator) {
          this.dataSource.paginator.firstPage();
        }
      }
    }

- . , , , , , . , , , .

    export interface Project {
        id: string;
        projectNumber: string;
        description: string;
        activePeriods: ProjectActivePeriod[];
    }

, , matColumnDef = "projectNumber" . ProjectNumber ', .

• stackblitz - , .
• pagination documentation

Answer 6

This is because your this.sort.sortChange method is called before your child views Initialize

You just need to implement your class from AfterViewInit instead of OnInit

And use the ngAfterViewInit lifecycle method

export class ApplicantListComponent implements AfterViewInit {
    @ViewChild(MatPaginator, { static: false }) paginator: MatPaginator;
    @ViewChild(MatSort, { static: false }) sort: MatSort;

    constructor() {}

    ngAfterViewInit() {
        this.sort.sortChange.subscribe(() => {
            this.paginator.pageIndex = 0;
            this.paginator.pageSize = this.pageSize;
        });
}