使用FormArray的Angular Material可编辑表

Question

我正在尝试使用最新材料+ cdk for angular来构建内联可编辑表格。

Question

如何使用mat-table使用[formGroupName]，以便表单字段可以通过其正确的表单路径引用？

这是我到目前为止所得到的：Complete StackBlitz example

模板

<form [formGroup]="form">
  <h1>Works</h1>
  <div formArrayName="dates" *ngFor="let date of rows.controls; let i = index;">
    <div [formGroupName]="i">
      <input type="date" formControlName="from" placeholder="From date">
      <input type="date" formControlName="to" placeholder="To date">
    </div>
  </div>


  <h1>Wont work</h1>
  <table mat-table [dataSource]="dataSource" formArrayName="dates">
    <!-- Row definitions -->
    <tr mat-header-row *matHeaderRowDef="displayColumns"></tr>
    <tr mat-row *matRowDef="let row; let i = index; columns: displayColumns;" [formGroupName]="i"></tr>

    <!-- Column definitions -->
    <ng-container matColumnDef="from">
      <th mat-header-cell *matHeaderCellDef> From </th>
      <td mat-cell *matCellDef="let row"> 
        <input type="date" formControlName="from" placeholder="From date">
      </td>
    </ng-container>

    <ng-container matColumnDef="to">
      <th mat-header-cell *matHeaderCellDef> To </th>
      <td mat-cell *matCellDef="let row">
        <input type="date" formControlName="to" placeholder="To date">
      </td>
    </ng-container>
  </table>
  <button type="button" (click)="addRow()">Add row</button>
</form>

零件

export class AppComponent implements  OnInit  {
  data: TableData[] = [ { from: new Date(), to: new Date() } ];
  dataSource = new BehaviorSubject<AbstractControl[]>([]);
  displayColumns = ['from', 'to'];
  rows: FormArray = this.fb.array([]);
  form: FormGroup = this.fb.group({ 'dates': this.rows });

  constructor(private fb: FormBuilder) { }

  ngOnInit() {
    this.data.forEach((d: TableData) => this.addRow(d, false));
    this.updateView();
  }

  emptyTable() {
    while (this.rows.length !== 0) {
      this.rows.removeAt(0);
    }
  }

  addRow(d?: TableData, noUpdate?: boolean) {
    const row = this.fb.group({
      'from'   : [d && d.from ? d.from : null, []],
      'to'     : [d && d.to   ? d.to   : null, []]
    });
    this.rows.push(row);
    if (!noUpdate) { this.updateView(); }
  }

  updateView() {
    this.dataSource.next(this.rows.controls);
  }
}

Problem

这不行。控制台产量

错误错误：找不到路径控件：'dates - > from'

似乎[formGroupName]="i"没有效果，因为使用formArray时路径应该是dates -> 0 -> from。

我当前的解决方法：对于这个问题，我绕过了内部路径查找（formControlName="from"）并直接使用表单控件：[formControl]="row.get('from')"，但我想知道我怎么能（或者至少为什么我不能）使用Reactive Form首选办法。

欢迎任何提示。谢谢。

---

因为我认为这是一个错误，我已经使用angular / material2 github repo注册了an issue。

Answer 1

我会使用matCellDef绑定中可以得到的索引：

*matCellDef="let row; let index = index" [formGroupName]="index"

Forked Stackblitz

Answer 2

这是示例代码

在Html中：

<form [formGroup]="tableForm">

<mat-table formArrayName="users" [dataSource]="dataSource">

  <ng-container cdkColumnDef="position">
    <mat-header-cell *cdkHeaderCellDef> No. </mat-header-cell>
    <mat-cell *cdkCellDef="let row let rowIndex = index"  [formGroupName]="rowIndex"> 
      <input type="text" size="2" formControlName="position"> </mat-cell>
  </ng-container>


  <ng-container cdkColumnDef="name">
    <mat-header-cell *cdkHeaderCellDef> Name </mat-header-cell>
    <mat-cell *cdkCellDef="let row let rowIndex = index"  [formGroupName]="rowIndex"> 
      <input type="text" size="7" formControlName="name">
    </mat-cell>
  </ng-container>

    <ng-container cdkColumnDef="weight">
    <mat-header-cell *cdkHeaderCellDef> Weight </mat-header-cell>
    <mat-cell *cdkCellDef="let row let rowIndex = index"  [formGroupName]="rowIndex"> 
      <input type="text" size="3" formControlName="weight">
    </mat-cell>
  </ng-container>

    <ng-container cdkColumnDef="symbol">
    <mat-header-cell *cdkHeaderCellDef> Symbol </mat-header-cell>
    <mat-cell *cdkCellDef="let row let rowIndex = index"  [formGroupName]="rowIndex"> 
      <input type="text" size="2" formControlName="symbol">
    </mat-cell>
  </ng-container>

  <!-- Header and Row Declarations -->
  <mat-header-row *cdkHeaderRowDef="displayedColumns"></mat-header-row>
  <mat-row *cdkRowDef="let row; columns: displayedColumns;"></mat-row>
</mat-table>
</form>

控制器代码：

displayedColumns: string[] = ['position', 'name', 'weight', 'symbol'];


 dataSource ;
  tableForm: FormGroup;



 constructor(private formBuilder: FormBuilder){
 this.dataSource = [
  {position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H'},
  {position: 2, name: 'Helium', weight: 4.0026, symbol: 'He'},
  {position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li'},
  {position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be'},
  {position: 5, name: 'Boron', weight: 10.811, symbol: 'B'},
  {position: 6, name: 'Carbon', weight: 12.0107, symbol: 'C'},
  {position: 7, name: 'Nitrogen', weight: 14.0067, symbol: 'N'},
  {position: 8, name: 'Oxygen', weight: 15.9994, symbol: 'O'},
  {position: 9, name: 'Fluorine', weight: 18.9984, symbol: 'F'},
  {position: 10, name: 'Neon', weight: 20.1797, symbol: 'Ne'},
];
  }

  ngOnInit(){
    this.tableForm= this.formBuilder.group({
        users: this.formBuilder.array([])
    })
    this.setUsersForm();
    this.tableForm.get('users').valueChanges.subscribe(users => {console.log('users', users)});
  }
  private setUsersForm(){
    const userCtrl = this.tableForm.get('users') as FormArray;
    this.dataSource.forEach((user)=>{
      userCtrl.push(this.setUsersFormArray(user))
    })
  };
  private setUsersFormArray(user){


    return this.formBuilder.group({
        position:[user.position],
        name:[user.name],
        weight:[user.weight], 
        symbol:[user.symbol]
    });
  }