一个组件中的多个材质分页在Angular中不起作用

Question

我尝试创建一个包含两个dataTables的组件，每个组件都带有另一个dataSource。由于我的原因，我的表格在加载组件后不可见，*ngIf因此我无法使用它，ngAfterViewInit()而使用的是用户在Github上指出的解决方案：

  private paginator: MatPaginator;
  private reportingPaginator: MatPaginator;
  private sort: MatSort;
  private reportingSort: MatSort;

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

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

  setDataSourceAttributes() {

      this.dataSource.paginator = this.paginator;
      this.dataSource.sort = this.sort;

      this.reportingDataSource.paginator = this.reportingPaginator;
      this.reportingDataSource.sort = this.reportingSort;

}

但是我仍然无法正常工作。当两个分页器都包含在中时，我的分页不起作用@ViewChild(MatPaginator)。如果我只包括其中一个

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

要么

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

我包括的那个很好用！那么，我需要做什么才能使两个分页器都正常工作？

Answer 1

对于单个页面中存在的多个MatPaginator和MatSort组件，您需要使用

@ViewChildren(MatPaginator) paginator = new QueryList<MatPaginator>();
@ViewChildren(MatSort) sort = new QueryList<MatSort>();

在您的代码中，该代码将返回您在页面中显示的MatSort和MatPaginator列表，这些列表按其显示的顺序定义。下面是完整的实现

import { Component, OnInit, ViewChild, ViewChildren, AfterViewInit, QueryList } from '@angular/core';
import { MatTableDataSource, MatSort, MatPaginator } from '@angular/material';

export interface AssignmentElement {
  assignmentId: number;
  action: string;
  userName: string;
  roleName: string;
  enabled: string;
  createdOn: string;
  createdBy: string;
  modifiedOn: string;
  modifiedBy: string;
  status: string;
}

export interface RoleElement {
  roleId: number;
  action: string;
  roleName: string;
  roleDescription: string;
  createdOn: string;
  createdBy: string;
  modifiedOn: string;
  modifiedBy: string;
  status: string;
}

export const ASSIGNMENT_ELEMENT_DATA: AssignmentElement[] = [
  { assignmentId: 1, action: 'Grant', userName: 'Dummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 2, action: 'Grant', userName: 'Dummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 3, action: 'Grant', userName: 'ADummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 4, action: 'Grant', userName: 'Dummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 8, action: 'Grant', userName: 'BDummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 1, action: 'Grant', userName: 'Dummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 12, action: 'Grant', userName: 'ZDummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 12, action: 'Grant', userName: 'Dummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 19, action: 'Grant', userName: 'Dummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 111, action: 'Grant', userName: 'PDummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 122, action: 'Grant', userName: 'Dummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { assignmentId: 133, action: 'Grant', userName: 'QDummy', roleName: 'admin', enabled: 'Y', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' }

];

export const ROLE_ELEMENT_DATA: RoleElement[] = [
  { roleId: 1, action: 'Create', roleName: 'admin', roleDescription: 'This is test role', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { roleId: 3, action: 'Create', roleName: 'cadmin', roleDescription: 'This is test role', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { roleId: 1, action: 'Create', roleName: 'admin', roleDescription: 'This is test role', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { roleId: 5, action: 'Create', roleName: 'vadmin', roleDescription: 'This is test role', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { roleId: 4, action: 'Create', roleName: 'zadmin', roleDescription: 'This is test role', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' },
  { roleId: 1, action: 'Create', roleName: 'admin', roleDescription: 'This is test role', createdOn: '21-Feb-2018', createdBy: 'Dummy', modifiedOn: '', modifiedBy: '', status: 'PENDING' }
];

@Component({
  selector: 'app-myqueue',
  templateUrl: './myqueue.component.html',
  styleUrls: ['./myqueue.component.css']
})
export class MyqueueComponent implements OnInit, AfterViewInit {

  dataSource1: MatTableDataSource<AssignmentElement>;
  dataSource2: MatTableDataSource<RoleElement>;
  @ViewChildren(MatPaginator) paginator = new QueryList<MatPaginator>();
  @ViewChildren(MatSort) sort = new QueryList<MatSort>();

  assignmentColumn: string[] = [
    'select', 'assignmentId', 'action', 'userName', 'roleName', 'enabled', 'createdOn', 'createdBy', 'modifiedOn', 'modifiedBy', 'status'
  ];
  roleColumn: string[] = [
    'select', 'roleId', 'action', 'roleName', 'roleDescription', 'createdOn', 'createdBy', 'modifiedOn', 'modifiedBy', 'status'
  ];

  constructor() {
    this.dataSource1 = new MatTableDataSource<AssignmentElement>(ASSIGNMENT_ELEMENT_DATA);
    this.dataSource2 = new MatTableDataSource<RoleElement>(ROLE_ELEMENT_DATA);
  }

  ngOnInit() {
  }

  ngAfterViewInit() {
    this.dataSource1.paginator = this.paginator.toArray()[0];
    this.dataSource1.sort = this.sort.toArray()[0];
    this.dataSource2.paginator = this.paginator.toArray()[1];
    this.dataSource2.sort = this.sort.toArray()[1];
  }

}

Answer 2

您也可以通过#id检索它们：

在您的HTML中：

<mat-paginator #categoryPaginator [pageSizeOptions]="[15]" hidePageSize="true" showFirstLastButtons="false"></mat-paginator>

在组件TS中：

@ViewChild('categoryPaginator', { read: MatPaginator }) categoryPaginator: MatPaginator;

编辑

After seeing gh0st's comment I did some digging and it seems the "read" option is supposed to be a boolean ViewChild angular documentation so I did an experiment and { read: true } does not work - but {read: false} does - but given false is the default removing it altogether still works - so it seems this is the most succinct way to do this is:

@ViewChild('categoryPaginator') categoryPaginator: MatPaginator;

I have tested this with 3 tables/paginators in the one view component and they appear to still work as expected.

I can only assume that { read: MatPaginator } is actually being interpreted as { read: false }

The Angular documentation does actually give a rough example of this:

A template reference variable as a string (e.g. query <my-component #cmp></my-component> with @ViewChild('cmp'))

EDIT-2

我遇到了一个场景，我在一个组件中有两个物料自动完成，并且需要访问其中的一个MatAutoComplete触发器-在这种情况下，看来{读取：MatAutocompleteTrigger}是必不可少的，否则它仅返回ElementRef：

@ViewChild('localityAutoComplete', { read: MatAutocompleteTrigger }) trigger: MatAutocompleteTrigger;