一个组件中的多个 material 分页在 Angular 中不起作用

Question

我尝试创建一个组件，其中包含两个数据表，每个数据表都有另一个数据源。由于我的 *ngIf，我的表在组件加载后不可见，因此我无法使用 ngAfterViewInit()，而是使用用户 pointed out on Github:[=19 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;

}

但我仍然无法让它工作。当两个分页器都包含在 @ViewChild(MatPaginator) 中时，我的分页不起作用。 如果我只包括一个分页器

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

或

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

我包含的那个工作正常！那么我需要做什么才能让两个分页器工作？

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，return 您将列出 MatSort 和 MatPaginator，这些列表按照它们在您页面中的显示顺序定义。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：

在你的HTML中：

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

在你的组件中 TS:

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

编辑

看到 gh0st 的评论后我做了一些挖掘，似乎 "read" 选项应该是一个布尔值 ViewChild angular documentation 所以我做了一个实验并且 { read: true } 不起作用 - 但是{read: false} 确实如此——但假设 false 是默认的，将其完全删除仍然有效——所以这似乎是最简洁的方法：

@ViewChild('categoryPaginator') categoryPaginator: MatPaginator;

我已经在一个视图组件中用 3 tables/paginators 测试了这个，它们似乎仍然按预期工作。

我只能假设 { read: MatPaginator } 实际上被解释为 { read: false }

Angular 文档实际上给出了一个粗略的例子：

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

EDIT-2

我遇到了这样一种情况，我在一个组件中有两个 material 自动完成，并且需要为其中一个访问 MatAutoComplete 触发器 - 在这种情况下似乎 { read: MatAutocompleteTrigger } 是必不可少的，否则它只是returns 一个元素引用：

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

一个组件中的多个 material 分页在 Angular 中不起作用

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