Angular - Material 表，是否可以在不刷新整个表的情况下更新行？

Question

经过几周的谷歌搜索和到目前为止只有一个 Stackoverflown 问题，我终于设法使用 Material Table Component 构建了我的 Angular CRUD 应用程序。它显示来自后端 (JSON) 的数据，对于 CRUD 操作，我使用的是如图所示的对话框(这是编辑，抱歉克罗地亚语)。对话框可能不是最好的方式，内联编辑可能更好。但是，要添加新项目，您仍然需要对话框之类的东西。

我坚持的最后一件事是如何相应地更新表中的字段。因此，当您在对话框中按“保存”时，数据会在后端(在 MySQL 表中)更新，但不会在前端更新。目前我有一个丑陋的解决方法，每次当你进行更新时，它也会刷新整个表。

无论如何这里的代码:

表格组件:

export class BazaComponent implements OnInit {
  ....
  constructor(public httpClient: HttpClient, public dialog: MatDialog) {
  }

  ngOnInit() {
    this.loadData();
  }

  // TODO: Simplfy this...
  addNew(ident: number, naziv: string, mt: number, kutija: number,
         komada: number, jm: string, orginal: number, lokacija: number, napomena: string) {
    console.log('add new clicked');
    const dialogRef = this.dialog.open(AddDialogComponent, {
      data: {ident: ident, naziv: naziv, mt: mt, kutija: kutija,
        komada: komada, jm: jm, orginal: orginal, lokacija: lokacija, napomena: napomena }
    });

    dialogRef.afterClosed().subscribe(result => {
      console.log(result);
      if (result === 1) {
        this.loadData();  // --> This is a temp workaround, every time when I do CRUD operation just redraw whole thing again
      }
    });
  }

  startEdit(id: number, ident: number, naziv: string, mt: number, kutija: number,
            komada: number, jm: string, orginal: number, lokacija: number, napomena: string) {

    const dialogRef = this.dialog.open(EditDialogComponent, {
      data: {id: id, ident: ident, naziv: naziv, mt: mt, kutija: kutija,
        komada: komada, jm: jm, orginal: orginal, lokacija: lokacija, napomena: napomena}
    });

    dialogRef.afterClosed().subscribe(result => {
      if (result === 1) {
        this.loadData(); // --> This is a temp workaround, every time when I do CRUD operation just redraw whole thing again
      }
    });
  }

  deleteItem(id: number, ident: number, naziv: string, mt: number) {
    const dialogRef = this.dialog.open(DeleteDialogComponent, {
      data: {id: id, ident: ident, naziv: naziv, mt: mt}
    });

    dialogRef.afterClosed().subscribe(result => {
      if (result === 1) {
        this.loadData();
      }
    });
  }


  public loadData() {
    this.exampleDatabase = new DataService(this.httpClient);
    this.dataSource = new ExampleDataSource(this.exampleDatabase, this.paginator, this.sort);
    Observable.fromEvent(this.filter.nativeElement, 'keyup')
      .debounceTime(150)
      .distinctUntilChanged()
      .subscribe(() => {
        if (!this.dataSource) {
          return;
        }
        this.dataSource.filter = this.filter.nativeElement.value;
      });
  }
}


export class ExampleDataSource extends DataSource<Baza> {
  _filterChange = new BehaviorSubject('');

  get filter(): string {
    return this._filterChange.value;
  }

  set filter(filter: string) {
    this._filterChange.next(filter);
  }

  filteredData: Baza[] = [];
  renderedData: Baza[] = [];

  constructor(private _exampleDatabase: DataService,
              private _paginator: MatPaginator,
              private _sort: MatSort) {
    super();
    // Reset to the first page when the user changes the filter.
    this._filterChange.subscribe(() => this._paginator.pageIndex = 0);
  }

  /** Connect function called by the table to retrieve one stream containing the data to render. */
  connect(): Observable<Baza[]> {
    // Listen for any changes in the base data, sorting, filtering, or pagination
    const displayDataChanges = [
      this._exampleDatabase.dataChange,
      this._sort.sortChange,
      this._filterChange,
      this._paginator.page,
    ];

    this._exampleDatabase.getAllItems();

    return Observable.merge(...displayDataChanges).map(() => {
      // Filter data
      this.filteredData = this._exampleDatabase.data.slice().filter((item: Baza) => {
        const searchStr = (item.ident + item.naziv + item.mt + item.lokacija + item.napomena).toLowerCase();
        return searchStr.indexOf(this.filter.toLowerCase()) !== -1;
      });

      // Sort filtered data
      const sortedData = this.sortData(this.filteredData.slice());

      // Grab the page's slice of the filtered sorted data.
      const startIndex = this._paginator.pageIndex * this._paginator.pageSize;
      this.renderedData = sortedData.splice(startIndex, this._paginator.pageSize);
      return this.renderedData;
    });
  }

  disconnect() {
  }

  /** Returns a sorted copy of the database data. */
  sortData(data: Baza[]): Baza[] {
  ... sort stuff
}

这是我想我应该进行字段更新的 DataService:

import { Injectable } from '@angular/core';
import { HttpClient, HttpErrorResponse, HttpHeaders} from '@angular/common/http';
import { Baza } from '../models/kanban.baza';
import { BehaviorSubject } from 'rxjs/BehaviorSubject';

    @Injectable()
    export class DataService {
      private readonly API_URL = 'http://localhost/api/'

      /** Stream that emits whenever the data has been modified. */
      dataChange: BehaviorSubject<Baza[]> = new BehaviorSubject<Baza[]>([]);

      constructor(private httpClient: HttpClient) {
      }

      get data(): Baza[] {
        return this.dataChange.value;
      }

      getAllItems(): void {
        this.httpClient.get<Baza[]>(this.API_URL).subscribe(data => {
          this.dataChange.next(data['items']);
        });
      }

    addItem(baza: Baza): void {
      this.httpClient.post(this.API_URL, Baza).subscribe(data => {
          //THIS WAS MY BEST TRY BUT IT DOESN'T WORK :(
          const copiedData = this.data.slice();
          copiedData.push(baza);
          console.log(copiedData);
          this.dataChange.next(copiedData);
      });
    }


      updateItem(baza: Baza): void {
        this.httpClient.put(this.API_URL + baza.id, baza).subscribe();
      }

      deleteItem(id: number): void {
        this.httpClient.delete(this.API_URL + id, {headers: new HttpHeaders().set('Access-Control-Allow-Origin', '*')} ).subscribe();
    }
}

2017 年 11 月 27 日更新:

好的，我终于想出了如何触发新行添加。我不得不在表组件中调用 dataChange.value。一旦你用一些数据加载它，新行就会立即出现。

const data = {id: 208, ident: 233, naziv: 'test', mt: 291, komada: 2, jm: 'a', orginal: 100, lokacija: 3, napomena: 'pls work'};
this.exampleDatabase.dataChange.value.push(data);

DataService 中的相同内容将不起作用:

this.dataChange.value.push(data); 

Plunker 在这里:

https://plnkr.co/edit/IWCVsBRl54F7ylGNIJJ3?p=info

编辑 28.11.2017:

现在唯一剩下的就是构建添加、编辑和删除的逻辑。因为添加很容易，它只是“value.push(data)”。感谢大家的帮助。

Answer 1

花了我一些时间，但我终于让一切正常。您的回答和不同的方法也有帮助。所以，如果有人遇到麻烦，这是我的 CRUD 实现:

https://github.com/marinantonio/angular-mat-table-crud

截图:

或者您可以查看项目演示: https://marinantonio.github.io/angular-mat-table-crud/

关键部分在table.ts文件中:

....
addNew(issue: Issue) {
    const dialogRef = this.dialog.open(AddDialogComponent, {
      data: {issue: issue }
    });

    dialogRef.afterClosed().subscribe(result => {
      if (result === 1) {
        this.exampleDatabase.dataChange.value.push(this.dataService.getDialogData());
        this.refreshTable();
      }
    });
  }

  startEdit(i: number, id: number, title: string, state: string, url: string, created_at: string, updated_at: string) {
    this.index = i;
    this.id2 = id;
    console.log(this.index);
    const dialogRef = this.dialog.open(EditDialogComponent, {
      data: {id: id, title: title, state: state, url: url, created_at: created_at, updated_at: updated_at}
    });

    dialogRef.afterClosed().subscribe(result => {
      if (result === 1) {
        // Part where we do frontend update, first you need to find record using id
        const foundIndex = this.exampleDatabase.dataChange.value.findIndex(x => x.id === this.id2);
        // Then you update that record using dialogData
        this.exampleDatabase.dataChange.value[foundIndex] = this.dataService.getDialogData();
        // And lastly refresh table
        this.refreshTable();
      }
    });
  }

  deleteItem(i: number, id: number, title: string, state: string, url: string) {
    this.index = i;
    this.id2 = id;
    const dialogRef = this.dialog.open(DeleteDialogComponent, {
      data: {id: id, title: title, state: state, url: url}
    });

    dialogRef.afterClosed().subscribe(result => {
      if (result === 1) {
        const foundIndex = this.exampleDatabase.dataChange.value.findIndex(x => x.id === this.id2);
        this.exampleDatabase.dataChange.value.splice(foundIndex, 1);
        this.refreshTable();
      }
    });
  }


  private refreshTable() {
    // If there's no data in filter we do update using pagination, next page or previous page
    if (this.dataSource._filterChange.getValue() === '') {
      if (this.dataSource._paginator.pageIndex === 0) {
        this.dataSource._paginator.nextPage();
        this.dataSource._paginator.previousPage();
      } else {
        this.dataSource._paginator.previousPage();
        this.dataSource._paginator.nextPage();
      }
      // If there's something in filter, we reset it to 0 and then put back old value
    } else {
      this.dataSource.filter = '';
      this.dataSource.filter = this.filter.nativeElement.value;
    }
}
....