我是新手。现在，我正在用Angular（7）开发原型。 原型应使用外部页面上的其余部分（AZURE）加载数据。我设法设置了请求，我可以看到控制台中提供的数据，但是我不知道如何初始化Material表以使用响应的数据来构建表，并且在Internet上找不到Angular版本的任何示例7。
我正在寻找一个代码示例，一旦我能设法理解就可以了。
这是响应中的JSON数据（我将其剪切以便使其适合帖子），我的ts文件是您在运行时获得的文件：
ng生成@ angular / material：material-table --name = accountlist
====accountlist.component.html====
<div class="mat-elevation-z8">
<table mat-table class="full-width-table" [dataSource]="accounts.data.Documents" matSort aria-label="Elements">
<!-- Id Column -->
<ng-container matColumnDef="ID">
<th mat-header-cell *matHeaderCellDef mat-sort-header>ID</th>
<td mat-cell *matCellDef="let row">{{row.ID}}</td>
</ng-container>
<!-- Name Column -->
<ng-container matColumnDef="Name">
<th mat-header-cell *matHeaderCellDef mat-sort-header>Name</th>
<td mat-cell *matCellDef="let row">{{row.Name}}</td>
</ng-container>
<!-- City Column -->
<ng-container matColumnDef="City">
<th mat-header-cell *matHeaderCellDef mat-sort-header>City</th>
<td mat-cell *matCellDef="let row">{{row.City}}</td>
</ng-container>
<!-- Country Column -->
<ng-container matColumnDef="Country">
<th mat-header-cell *matHeaderCellDef mat-sort-header>Country</th>
<td mat-cell *matCellDef="let row">{{row.Country}}</td>
</ng-container>
<tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
<tr mat-row *matRowDef="let row; columns: displayedColumns;"></tr>
</table>
<mat-paginator #paginator
[length]="accounts.data.Documents.length"
[pageIndex]="0"
[pageSize]="50"
[pageSizeOptions]="[25, 50, 100, 250]">
</mat-paginator>
</div>
====accountlist.comoponent.ts====
import { Component, OnInit, ViewChild } from '@angular/core';
import { MatPaginator, MatSort } from '@angular/material';
import { AccountlistDataSource } from './accountlist-datasource';
import { AzureService } from './../_services/azure.service';
@Component({
selector: 'app-accountlist',
templateUrl: './accountlist.component.html',
styleUrls: ['./accountlist.component.css']
})
export class AccountlistComponent implements OnInit {
@ViewChild(MatPaginator) paginator: MatPaginator;
@ViewChild(MatSort) sort: MatSort;
dataSource: AccountlistDataSource;
public accounts: any;
constructor(private azureService: AzureService) {
}
/** Columns displayed in the table. Columns IDs can be added, removed, or reordered. */
displayedColumns = ['ID', 'Name', 'City', 'Country'];
readAccountsAzure(): void {
this.azureService.getAccountsAzure()
.subscribe(
accounts => {
this.accounts = accounts;
console.log(this.accounts.Documents);
}
);
}
RenderDataTable() {
this.azureService.getAccountsAzure()
.subscribe(
res => {
this.accounts = new AccountlistDataSource(this.paginator, this.sort);
this.accounts.data = res as Account[];
console.log(this.accounts);
},
error => {
console.log('There was an error while retrieving data !!!' + error);
});
}
ngOnInit() {
this.RenderDataTable();
// this.accounts = new AccountlistDataSource(this.paginator, this.sort);
}
}
====accountlist-datasource.ts====
import { AzureService } from './../_services/azure.service';
import { DataSource } from '@angular/cdk/collections';
import { MatPaginator, MatSort } from '@angular/material';
import { map } from 'rxjs/operators';
import { Observable, of as observableOf, merge } from 'rxjs';
// TODO: Replace this with your own data model type
export interface AccountlistItem {
name: string;
id: number;
}
// TODO: replace this with real data from your application
const EXAMPLE_DATA: AccountlistItem[] = [
{id: 1, name: 'Hydrogen'},
{id: 2, name: 'Helium'},
{id: 3, name: 'Lithium'},
{id: 4, name: 'Beryllium'},
{id: 5, name: 'Boron'},
{id: 6, name: 'Carbon'},
{id: 7, name: 'Nitrogen'},
{id: 8, name: 'Oxygen'},
{id: 9, name: 'Fluorine'},
{id: 10, name: 'Neon'},
{id: 11, name: 'Sodium'},
{id: 12, name: 'Magnesium'},
{id: 13, name: 'Aluminum'},
{id: 14, name: 'Silicon'},
{id: 15, name: 'Phosphorus'},
{id: 16, name: 'Sulfur'},
{id: 17, name: 'Chlorine'},
{id: 18, name: 'Argon'},
{id: 19, name: 'Potassium'},
{id: 20, name: 'Calcium'},
];
/**
* Data source for the Accountlist view. This class should
* encapsulate all logic for fetching and manipulating the displayed data
* (including sorting, pagination, and filtering).
*/
export class AccountlistDataSource extends DataSource<AccountlistItem> {
// data: AccountlistItem[] = EXAMPLE_DATA;
data: AccountlistItem[];
constructor(private paginator: MatPaginator, private sort: MatSort) {
super();
}
/**
* Connect this data source to the table. The table will only update when
* the returned stream emits new items.
* @returns A stream of the items to be rendered.
*/
connect(): Observable<AccountlistItem[]> {
// Combine everything that affects the rendered data into one update
// stream for the data-table to consume.
const dataMutations = [
observableOf(this.data),
this.paginator.page,
this.sort.sortChange
];
// Set the paginator's length
this.paginator.length = this.data.length;
return merge(...dataMutations).pipe(map(() => {
return this.getPagedData(this.getSortedData([...this.data]));
}));
}
/**
* Called when the table is being destroyed. Use this function, to clean up
* any open connections or free any held resources that were set up during connect.
*/
disconnect() {}
/**
* Paginate the data (client-side). If you're using server-side pagination,
* this would be replaced by requesting the appropriate data from the server.
*/
private getPagedData(data: AccountlistItem[]) {
const startIndex = this.paginator.pageIndex * this.paginator.pageSize;
return data.splice(startIndex, this.paginator.pageSize);
}
/**
* Sort the data (client-side). If you're using server-side sorting,
* this would be replaced by requesting the appropriate data from the server.
*/
private getSortedData(data: AccountlistItem[]) {
if (!this.sort.active || this.sort.direction === '') {
return data;
}
return data.sort((a, b) => {
const isAsc = this.sort.direction === 'asc';
switch (this.sort.active) {
case 'name': return compare(a.name, b.name, isAsc);
case 'id': return compare(+a.id, +b.id, isAsc);
default: return 0;
}
});
}
}
/** Simple sort comparator for example ID/Name columns (for client-side sorting). */
function compare(a, b, isAsc) {
return (a < b ? -1 : 1) * (isAsc ? 1 : -1);
}
====JSON RESPONSE====
{
"_rid":"R-UdANZutGw=",
"Documents":[
{
"id":"c5826db5-d68b-4be8-84ed-c4cc3c15cd5a",
"_rid":"R-UdANZutGwJAAAAAAAAAA==",
"_self":"dbs\/R-UdAA==\/colls\/R-UdANZutGw=\/docs\/R-UdANZutGwJAAAAAAAAAA==\/",
"_etag":"\"06000f28-0000-0c00-0000-5c34d2830000\"",
"Account Number":"232342-555445",
"Country":"Germany",
"Created Date":"01/10/2018",
"Currency":"US Dollar",
"ID":"8adc8f99661fc13b01662f31eeb413dc",
"Name":"85255-1545445",
"SHS_SAP_SOLD_TO":"US_0000001234",
"Status":"Active",
"Address 1":"",
"Address 2":"",
"City":"",
"County":"",
"Postal Code":"",
"State/Province":"",
"_attachments":"attachments\/",
"_ts":1546965635
},
{
"id":"1f990cdf-d64c-49d4-b6bc-4fdc91462d2c",
"_rid":"R-UdANZutGwvAQAAAAAAAA==",
"_self":"dbs\/R-UdAA==\/colls\/R-UdANZutGw=\/docs\/R-UdANZutGwvAQAAAAAAAA==\/",
"_etag":"\"06003529-0000-0c00-0000-5c34d2830000\"",
"Account Number":"90164412-100532",
"Country":"Germany",
"Created Date":"01/10/2018",
"Currency":"US Dollar",
"ID":"8adce421661fcddc01662f3263836dfb",
"Name":"15151-45100532",
"SHS_SAP_SOLD_TO":"US_0000001234",
"Status":"Active",
"Address 1":"",
"Address 2":"",
"City":"",
"County":"",
"Postal Code":"",
"State/Province":"",
"_attachments":"attachments\/",
"_ts":1546965635
},
{
"id":"185e8238-2287-4989-b7f1-d69ffa4f65fe",
"_rid":"R-UdANZutGwwAQAAAAAAAA==",
"_self":"dbs\/R-UdAA==\/colls\/R-UdANZutGw=\/docs\/R-UdANZutGwwAQAAAAAAAA==\/",
"_etag":"\"06003629-0000-0c00-0000-5c34d2830000\"",
"Account Number":"3432423-324234",
"Country":"Germany",
"Created Date":"01/10/2018",
"Currency":"US Dollar",
"ID":"8adce421661fcddc01662f3242d86dda",
"Name":"23432423-324234",
"SHS_SAP_SOLD_TO":"US_0000001234",
"Status":"Active",
"Address 1":"",
"Address 2":"",
"City":"",
"County":"",
"Postal Code":"",
"State/Province":"",
"_attachments":"attachments\/",
"_ts":1546965635
},
{
"id":"7894ab52-9d3d-498d-a162-c9b57702c650",
"_rid":"R-UdANZutGwxAQAAAAAAAA==",
"_self":"dbs\/R-UdAA==\/colls\/R-UdANZutGw=\/docs\/R-UdANZutGwxAQAAAAAAAA==\/",
"_etag":"\"06003729-0000-0c00-0000-5c34d2830000\"",
"Account Number":"234234-234234",
"Country":"Germany",
"Created Date":"01/10/2018",
"Currency":"US Dollar",
"ID":"8adce421661fcddc01662f323f406dd6",
"Name":"234234-234234",
"SHS_SAP_SOLD_TO":"US_0000001234",
"Status":"Active",
},
{
"id":"f274b1e9-7bac-48e8-8931-e98b7e8be046",
"_rid":"R-UdANZutGzvAwAAAAAAAA==",
"_self":"dbs\/R-UdAA==\/colls\/R-UdANZutGw=\/docs\/R-UdANZutGzvAwAAAAAAAA==\/",
"_etag":"\"0600f52b-0000-0c00-0000-5c34d2890000\"",
"Account Number":"324234-23423",
"Country":"Germany",
"Created Date":"01/10/2018",
"Currency":"US Dollar",
"ID":"8adc8f99661fc13b01662f34da211779",
"Name":"Default Account",
"SHS_SAP_SOLD_TO":"US_0000001234",
"Status":"Active",
"Address 1":"",
"Address 2":"",
"City":"",
"County":"",
"Postal Code":"",
"State/Province":"",
"_attachments":"attachments\/",
"_ts":1546965641
},
{
"id":"415ff345-5ecd-4bfd-b20b-fd8cc7186744",
"_rid":"R-UdANZutGzwAwAAAAAAAA==",
"_self":"dbs\/R-UdAA==\/colls\/R-UdANZutGw=\/docs\/R-UdANZutGzwAwAAAAAAAA==\/",
"_etag":"\"0600f62b-0000-0c00-0000-5c34d2890000\"",
"Account Number":"324234-234234",
"Country":"Germany",
"Created Date":"01/10/2018",
"Currency":"US Dollar",
"ID":"8adc8f99661fc13b01662f34cc801765",
"Name":"324234234",
"SHS_SAP_SOLD_TO":"US_0000001234",
"Status":"Active",
"Address 1":"",
"Address 2":"",
"City":"",
"County":"",
"Postal Code":"",
"State/Province":"",
"_attachments":"attachments\/",
"_ts":1546965641
}
],
"_count":1000
}
控制台日志显示第16行的HTML文件中存在错误。 AccountlistComponent.html：16错误TypeError：无法读取未定义的属性“数据”
但是我认为问题实际上与数据可能无法正确加载的事实有关
感谢您的支持：-）
答案 0 :(得分：1)
该错误消息告诉您它无法从data读取undefined。这意味着，查看您的HTML代码，[length]="dataSource.data.length"失败了，因为dataSource没有被初始化。
length的全部要为固定值，否则它将始终在一页上。因此，只需放入length="50"或其他任何内容。或者，如果出于任何原因要坚持使用长度，则可能需要[length]="accounts.length"。
在编辑并指定问题之前： 您可以在official Angular documentation中找到各种带有相关代码的示例。
您拥有数据，因此只需使用正确的MatTableDataSource成员在组件代码中正确设置变量即可。
答案 1 :(得分：0)
您忘记在 dataSource 中初始化 data 变量。因此，在页面加载时，它会发现 dataSource.data 未定义并引发错误。在您的ngOnInit（）中，为 dataSource 初始化 data 变量。
ngOnInit() {
dataSource.data = [];
. . .
}