我坚持在Angular 4中创建一个可重用的组件。我有一堆报告都包含一个搜索表单(每个报告的字段不同)和一个材料表结果列表(字段列表不同于每个报告)。当我为每个报告复制整个组件时,它按预期工作,但我想将其重构为可重用的组件/模板和扩展它的子组件。但范围都是错误的,我无法理解这是如何工作的。
report.component.ts (可重用组件)
import {Component, ViewChild} from '@angular/core';
import {MatPaginator} from '@angular/material';
import 'rxjs/add/operator/map';
import {ReportsDataSource} from '../services/reports-datasource.service';
@Component({
selector: 'app-report',
templateUrl: './report.component.html',
})
export class ReportComponent {
@ViewChild(MatPaginator) paginator: MatPaginator;
/** result table columns */
columns = [];
/** Column definitions in order */
displayedColumns = this.columns.map(x => x.columnDef);
/** empty search parameters object, used for form field binding */
/** datasource service */
dataSource: ReportsDataSource;
/** submit the form */
getData() {
this.dataSource.getData();
}
}
report.component.html (可重复使用的模板)
<form (ngSubmit)="getData()" #ReportSearchForm="ngForm">
<ng-content select=".container-fluid"></ng-content>
<button type="submit" mat-button class="mat-primary" [disabled]="!ReportSearchForm.form.valid">Search</button>
</form>
<mat-table #table [dataSource]="dataSource">
<ng-container *ngFor="let column of columns" [matColumnDef]="column.columnDef">
<mat-header-cell *matHeaderCellDef>{{ column.header }}</mat-header-cell>
<mat-cell *matCellDef="let row">{{ column.cell(row) }}</mat-cell>
</ng-container>
<mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
<mat-row *matRowDef="let row; columns: displayedColumns;"></mat-row>
</mat-table>
<mat-paginator #paginator
[length]="dataSource ? dataSource.meta.total_results : 0"
[pageSize]="dataSource ? dataSource.meta.per_page : 25"
[pageSizeOptions]="[10, 25, 50, 100]"
>
</mat-paginator>
childreport.component.ts (特定报告)
import {Component, OnInit} from '@angular/core';
import {ReportComponent} from '../report.component';
import {ChildreportService} from './childreport.service';
import {ReportsDataSource} from '../../services/reports-datasource.service';
@Component({
selector: 'app-report-child',
templateUrl: './childreport.component.html',
providers: [ChildreportService, ReportsDataSource]
})
export class ChildreportComponent extends ReportComponent implements OnInit {
constructor(private childreportService: ChildreportService) {
super();
}
/** result table columns */
columns = [
{columnDef: 'column1', header: 'Label 1', cell: (row) => `${row.column1}`},
{columnDef: 'column2', header: 'Label 2', cell: (row) => `${row.column2}`}
];
ngOnInit() {
this.dataSource = new ReportsDataSource(this.ChildreportService, this.paginator);
}
}
childreport.component.html (此报告的搜索表单嵌入在父模板中)
<app-report>
<div class="container-fluid">
<mat-form-field>
<input matInput placeholder="some field" name="fieldx">
</mat-form-field>
</div>
</app-report>
什么有效:我得到主模板中嵌入的表单,没有错误。
什么行不通:表单和表格绑定到ReportComponent
而不是ChildreportComponent
。我有点理解为什么会发生这种情况(因为这个模板的范围就是那个组件)但是我不知道我怎么能继承#34;模板,并在ChildreportComponent
范围内。我错过了什么?
答案 0 :(得分:2)
我自己想通了。事实上,解决方案相当简单。我的错误是在我的report.component中同时尝试两件事,提供模板和逻辑。我最终得到的是一个抽象组件,它包含逻辑并由每个报告扩展,以及每个报告中相似部分的几个较小组件(shell,结果列表等)。我也从模板表格切换到反应形式。
report-base.component.ts 包含公共逻辑
import {OnInit} from '@angular/core';
import {FormBuilder, FormGroup} from '@angular/forms';
import {MatPaginator, MatSidenav} from '@angular/material';
import 'rxjs/add/operator/map';
import {ReportsDataSource} from '../common/services/reports-datasource.service';
import {ReportsService} from '../common/services/reports.service';
import {ReportsResultlistService} from '../common/services/reports-resultlist.service';
export abstract class ReportBaseComponent implements OnInit {
constructor(
protected _formBuilder: FormBuilder, protected _reportService: ReportsService, protected _resultlistService: ReportsResultlistService) {
}
/**
* For toggling the search form and resultlist action buttons
* @type {boolean}
*/
protected hasResults = false;
/** Default data source for the table */
protected dataSource: ReportsDataSource;
/** search form controls */
protected searchForm: FormGroup;
/** result table columns */
protected columns = [];
ngOnInit() {
this.createForm();
this.dataSource = new ReportsDataSource(this._reportService, this._resultlistService);
}
/**
* Builds the searchForm Group
*/
protected createForm() {
// create an empty form
this.searchForm = this._formBuilder.group({});
}
/**
* Submits the form/loads data (f.ex. pagination)
*/
protected getData() {
this.hasResults = true;
this.dataSource.search = this.searchForm.value;
this.dataSource.getData();
}
}
report-shell.component.ts 是一个CHILD组件(我的逻辑错误之一),提供组件周围的shell:
import {Component, Input} from '@angular/core';
import {ActivatedRoute} from '@angular/router';
@Component({
selector: 'app-report-shell',
templateUrl: './report-shell.component.html',
})
export class ReportShellComponent {
constructor(private route: ActivatedRoute) {
this.title = route.routeConfig.data['caption'];
}
@Input() hasResults = false;
title: string;
}
report-shell.component.html 提供搜索表单和结果列表周围的HTML
<mat-expansion-panel [expanded]="!hasResults">
<mat-expansion-panel-header>
Search
</mat-expansion-panel-header>
<ng-content select="form"></ng-content>
</mat-expansion-panel>
<div class="result-list">
<mat-toolbar class="result-header"><span>{{ title }}</span>
<span class="fill-remaining-space"></span>
<button class="fa fa-file-excel-o" (click)="exportExcel()"></button>
</mat-toolbar>
<ng-content select=".result-table"></ng-content>
</div>
因此,我的报告扩展了报告库,只需使用shell als a child:
childreport.component.ts 是一种特定报告,仅实现此报告的具体内容
import {Component, OnInit} from '@angular/core';
import {FormBuilder, Validators} from '@angular/forms';
import {ReportChildreportService} from './childreport.service';
import {ReportsDataSource} from '../../common/services/reports-datasource.service';
import {ReportsResultlistService} from '../../common/services/reports-resultlist.service';
import {ReportBaseComponent} from '../report-base.component';
@Component({
selector: 'app-report-dispatches',
templateUrl: './dispatches.component.html',
providers: [ReportChildreportService, ReportsResultlistService, ReportsDataSource]
})
export class ReportDispatchesComponent extends ReportBaseComponent implements OnInit {
constructor(protected _reportService: ReportChildreportService, protected _formBuilder: FormBuilder, protected _resultlistService: ReportsResultlistService) {
super(_formBuilder, _reportService, _resultlistService);
}
/** result table columns */
columns = [
{columnDef: 'name', header: 'Name', cell: (row) => `${row.name}`}
];
createForm() {
this.searchForm = this._formBuilder.group({
name: ''
});
}
}
<强> childreport.component.html 强>
<app-report-shell [hasResults]="hasResults">
<form (ngSubmit)="getData()" [formGroup]="searchForm" novalidate>
<mat-form-field>
<input matInput placeholder="search for a name" name="name" formControlName="name">
<mat-error>Invalid name</mat-error>
</mat-form-field>
</div>
</div>
<app-form-buttons [status]="searchForm.status"></app-form-buttons>
</form>
<app-report-result-list
[(dataSource)]="dataSource"
[columns]="columns"
[displayedColumns]="displayedColumns"
class="result-table"
></app-report-result-list>
</app-report-shell>
我不会详细了解表单和结果列表组件,这个答案很长,因为它是: - )
所以我设法减少了很多代码重复,尽管仍然有一些(除了表单之外,还在childreport.component.html中)。
答案 1 :(得分:0)
我建议你看看this article。 @WjComponent装饰器可能会为您提供有关您的方法的线索。 我从文章中理解的是,您需要一个新的组件装饰器来共享基类和子类之间的属性。
文章引用:
@Component({ selector: 'inherited-grid'
})
export class InheritedGrid extends wjGrid.WjFlexGrid {
...
}
现在我们有了组件的新元素名称!但是我们错过了基础WjFlexGrid类的装饰器中定义的所有其他必要设置。例如,WjFlexGrid的装饰器为输入装饰器属性分配可用于标记中绑定的网格属性数组。我们在新组件中丢失了它,如果你现在尝试绑定它们,你会发现绑定不起作用。
答案:Wijmo为Angular 2模块提供的@WjComponent装饰器。它的使用方式与标准的@Component装饰器相同,并且接受所有@Component装饰器的属性(加上一些特定于Wijmo的属性),但它的主要好处是它将其属性值与基类装饰器提供的属性合并。因此,组件定义的最后一步是用@WjComponent替换@Component: 从&#39; wijmo / wijmo.angular2.directiveBase&#39;;
导入{WjComponent}
@WjComponent({
selector: 'inherited-grid'
})
export class InheritedGrid extends wjGrid.WjFlexGrid {
...
}
我们可能已经使用“inherited-grid”名称重新定义了装饰器的selector属性,但是所有其他必要的属性(如输入和输出)都是从基础WjFlexGrid组件的装饰器中获取的。现在,element创建了我们的InheritedGrid组件,所有属性和事件绑定都正常运行!
另一种方法可能是将ReportComponent定义为指令,并通过@Host decorator在ChildReport和基础之间共享数据。
您还可以查看ngx-datatable的源代码。他们的示例和组件的源代码非常有用,可以为您提供有关在组件和覆盖模板之间共享数据的想法。