Question

我有来自后端的数据流，我看到它在控制台中打印现在我正在尝试将事件推送到dataSource它的抛出错误dataSource未定义。有人可以帮助如何动态添加数据以实现表格吗？

stream.component.html

<mat-table #table [dataSource]="dataSource"></mat-table>

stream.component.ts

import {
    Component,
    OnInit
} from '@angular/core';
import {
    StreamService
} from '../stream.service';
import {
    MatTableDataSource
} from '@angular/material';
import * as io from 'socket.io-client';

@Component({
    selector: 'app-stream',
    templateUrl: './stream.component.html',
    styleUrls: ['./stream.component.css']
})
export class StreamComponent implements OnInit {
    displayedColumns = ['ticketNum', "assetID", "severity", "riskIndex", "riskValue", "ticketOpened", "lastModifiedDate", "eventType"];
    dataSource: MatTableDataSource < Element[] > ;
    socket = io();

    constructor(private streamService: StreamService) {};

    ngOnInit() {
        this.streamService.getAllStream().subscribe(stream => {
            this.dataSource = new MatTableDataSource(stream);
        });
        this.socket.on('newMessage', function(event) {
            console.log('Datasource', event);
            this.dataSource.MatTableDataSource.filteredData.push(event);
        });
    }
}


export interface Element {
    ticketNum: number;
    ticketOpened: number;
    eventType: string;
    riskIndex: string;
    riskValue: number;
    severity: string;
    lastModifiedDate: number;
    assetID: string;
}

Answer 1

我找到了解决这个问题的方法，基本上如果你这样做了：

this.dataSource.data.push(newElement); //Doesn't work

但是如果你替换完整的数组，那么它可以正常工作。所以你的最终代码必须是：

this.socket.on('newMessage', function(event) {
    const data = this.dataSource.data;
    data.push(event);
    this.dataSource.data = data;
});

您可以在此处查看问题 - ＆gt; https://github.com/angular/material2/issues/8381

Answer 2

以下解决方案适用于 Angular 5.2.3 和 Angular Material 5.1.1 ：

this.socket.on('newMessage', function(event) {
    this.dataSource.data.push(event);
    this.dataSource.data = this.dataSource.data.slice();
});

Answer 3

来自docs

由于表针对性能进行了优化，因此不会自动检查数据数组的更改。相反，当在数据数组上添加，删除或移动对象时，可以通过调用表的renderRows（）方法来触发对表的渲染行的更新。

因此，您可以使用ViewChild和refreshRow（）

@ViewChild('table', { static: true }) table
  add() {

    this.dataSource.data.push(ELEMENT_DATA[this.index++])
    this.table.renderRows()
  }

我在stackblitz

中放了一个简单的例子

Answer 4

除了不使用单独的数组然后将其分配给// Array of double ArrayUP<double> pBuffer = MemHelper::MakeAUP<double>(2ui64 * nItems); // Single Connection SingleUP<Connection> pConn = MemHelper::MakeSUP<Connection>(ioContext);数据外，我们还可以使用ES6扩展运算符；如果您不使用ES6 +分配{{1}，则可以使用dataSource }数据保存到新数组。

在ES6 +中

concat

ECMAscript版本3 +

dataSource

Answer 5

对我来说，这些答案都没有用。可以观察到我订阅了获取新数据。唯一适合我的解决方案是：

 this.dataService.pointsNodesObservable.subscribe((data) => {
  this.dataSource = new InsertionTableDataSource(this.paginator, this.sort, this.dataService);
  this.dataSource.data = data;
});

呈现像魅力一样！

Answer 6

在创建选择行并对行数据应用某些操作时，我陷入了同样的问题。解决您问题的方法

imports..................
import { MatTableDataSource } from '@angular/material';
@component({ ...

export class StreamComponent implements OnInit {
// Initialise MatTableDataSource as empty
dataSource = new MatTableDataSource<Element[]>();

constructor() {}
...
// if you simply push data in dataSource then indexed 0 element remain undefined
// better way to do this as follows
 this.dataSource.data = val as any;

  // for your problem

   ngOnInit() {
  // ** important note .... I am giving solution assuming the subscription data is array of objects. Like in your case stream and in second event(parameter as callback)
    this.streamService.getAllStream().subscribe(stream => {
       // do it this way
        this.dataSource.data = stream as any;
     // note if you simply put it as 'this.dataSource.data = stream' then TS show you error as '[ts] Type 'string' is not assignable to type '{}[]''
    });
    this.socket.on('newMessage', (event) => {
        console.log('Datasource', event);
          // for this value
       // this.dataSource.MatTableDataSource.filteredData.push(event);   // I couldn't get what you are doing here 
     // SO try to explain what you are getting in this callback function val as event parameter ????????????????? 
     // but you can get it this ways

       this.dataSource.filteredData = event as any;
    });
  }

希望这对您有帮助。如果您有任何问题，请ping我。

Answer 7

这是一个非常简单容易的解决方案：

displayedColumns = ['ticketNum', 'assetID', 'severity', 'riskIndex', 'riskValue', 'ticketOpened', 'lastModifiedDate', 'eventType'];
dataSource: any[] = [];

constructor() { 

}

ngOnInit() {

}

onAdd() {  //If you want to add a new row in the dataSource
   let model = { 'ticketNum': 1, 'assetID': 2, 'severity': 3, 'riskIndex': 4, 'riskValue': 5, 'ticketOpened': true, 'lastModifiedDate': "2018-12-10", 'eventType': 'Add' };  //get the model from the form
   this.dataSource.push(model);  //add the new model object to the dataSource
   this.dataSource = [...this.dataSource];  //refresh the dataSource
}

希望这会有所帮助：）

如何动态地将数据添加到mat-table dataSource？

7 个答案: