css - Angular 6 - Ng-Container - Mat-table 内的 Ng-Template 不工作

Question

我正在从 API 将数据加载到 mat-table 数据源中。有一个 addnewrow() 方法可以在顶部添加一个新行。我实际上是在尝试使表的第一列可编辑。 (即)用户只有在创建新行时才能提供输入。表中的其余数据不应是可编辑的。因此，为此我默认使用本地标志变量 false。基于标志，我正在使用 ng-container. 创建 ng-template。如果是新行，则第一列是唯一可编辑的列，否则应该不可编辑。我不知道为什么这不起作用。

预期:

• 只有新添加行的第一列应该是可编辑的
• 保存在本地存储中。

请查看minimal demo - stackblitz ，因为我没有权利分享实际的片段，我很抱歉。

请分享任何工作示例和实现目标的最佳方法。

片段

<table mat-table #methedofaccept [dataSource]="dataSource" class="mat-elevation-z8" id= "tbl">              
  <ng-container *ngIf= "isColumnEditable == true; then showInputField  else normalColumn ">
    <th mat-header-cell *matHeaderCellDef> List of Values </th>
  </ng-container>
            
  <ng-template #showInputField>
    <td mat-cell matColumnDef="title" *matCellDef="let element" >
      <mat-form-field >
        <input matInput  [value]="element.title" [(ngModel)]="element.title">
      </mat-form-field>
    </td>
  </ng-template>

  <ng-template #normalColumn>
    <div matColumnDef="title">                    
      <td mat-cell *matCellDef="let element"> {{element.title}} </td>
    </div>
  </ng-template>

              
  <ng-container matColumnDef="action">
    <th mat-header-cell *matHeaderCellDef> Action </th>
    <td mat-cell *matCellDef="let element">                        
      <i *ngIf="element.endDate == null " class="material-icons clickable" (click)="deleteRow(element)">delete</i>
      <i *ngIf="element.endDate != null" class="material-icons clickable ct-blue undo-icon" (click)="undoRow(element)">undo</i>          
    </td>
  </ng-container>
  <tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
  <tr mat-row *matRowDef="let row; columns: displayedColumns;" [ngClass]="{'row-deleted': row['isDeleted']" >
  </tr>
</table>

ERROR TypeError: Cannot read property 'template' of undefined

谢谢

Answer 1

我从你的问题中得到了什么:

1. 使表的第一列可编辑，即用户只有在创建新行时才能输入。表中的其余数据不应是可编辑的
2. 保存在本地存储中。

在your stackblitz , 使 table-filtering-example.html 成为:

<div class="example-container mat-elevation-z8">


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

    <!-- Position Column -->
    <ng-container matColumnDef="position">
      <mat-header-cell *matHeaderCellDef> No. </mat-header-cell>
      <mat-cell *matCellDef="let element"> 
        <ng-container *ngIf='element.editable'>
        <input type="number" [(ngModel)]=element.position (ngModelChange)="inputChanged($event)" />
        </ng-container>
        <ng-container *ngIf='!element.editable'>
        {{element.position}} 
        </ng-container>
      </mat-cell>
    </ng-container>

    <!-- Name Column -->
    <ng-container matColumnDef="name">
      <mat-header-cell *matHeaderCellDef> Name </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.name}} </mat-cell>
    </ng-container>

    <!-- Weight Column -->
    <ng-container matColumnDef="weight">
      <mat-header-cell *matHeaderCellDef> Weight </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.weight}} </mat-cell>
    </ng-container>

    <!-- Symbol Column -->
    <ng-container matColumnDef="symbol">
      <mat-header-cell *matHeaderCellDef> Symbol </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.symbol}} </mat-cell>
    </ng-container>

    <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
    <mat-row *matRowDef="let row; columns: displayedColumns;"></mat-row>
  </mat-table>
</div>
<button (click)="addNewRow()">Add new row</button>

在your stackblitz , 使 table-filtering-example.ts 成为:

import { Component, ViewChild,  AfterViewInit } from '@angular/core';
import { MatTableDataSource, MatTable } from '@angular/material';

/**
 * @title Table with filtering
 */
@Component({
  selector: 'table-filtering-example',
  styleUrls: ['table-filtering-example.css'],
  templateUrl: 'table-filtering-example.html',
})
export class TableFilteringExample implements AfterViewInit {
  @ViewChild('table') table: MatTable<Element>;
  displayedColumns = ['position', 'name', 'weight', 'symbol'];
  // dataSource = new MatTableDataSource([]);
  data: Element[] = [];

  constructor(){  
    console.log(this.data);
  }

  ngAfterViewInit(){
    if (this.table){
      //console.log('got table');
      if (this.table.dataSource) {
        this.data = (this.table.dataSource as Element[]);
      }  
      this.data.push(ELEMENT_DATA[this.data.length]);
      this.data.push(ELEMENT_DATA[this.data.length]);
      this.data.push(ELEMENT_DATA[this.data.length]);
      this.data.push(ELEMENT_DATA[this.data.length]);
      this.table.dataSource = this.data;
      this.table.renderRows();
    }
  }

  inputChanged(event){
    this.updateLocalStorage();
  }

  updateLocalStorage(){
      localStorage.setItem('myArray', JSON.stringify(this.table.dataSource) );
  }

  addNewRow() {
    let data: Element[] = [];
    if (this.table.dataSource) {
      data = (this.table.dataSource as Element[]);
    }
    ELEMENT_DATA[data.length].editable =true;
    data.push(ELEMENT_DATA[data.length]);
    this.table.dataSource = data;
    this.table.renderRows();
  }
}

export interface Element {
  name: string;
  position: number;
  weight: number;
  symbol: string;
  editable: boolean;
}

const ELEMENT_DATA: Element[] = [
  {position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H', editable: false},
  {position: 2, name: 'Helium', weight: 4.0026, symbol: 'He', editable: false},
  {position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li', editable: false},
  {position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be', editable: false},
  {position: 5, name: 'Boron', weight: 10.811, symbol: 'B', editable: false},
  {position: 6, name: 'Carbon', weight: 12.0107, symbol: 'C', editable: false},
  {position: 7, name: 'Nitrogen', weight: 14.0067, symbol: 'N', editable: false},
  {position: 8, name: 'Oxygen', weight: 15.9994, symbol: 'O', editable: false},
  {position: 9, name: 'Fluorine', weight: 18.9984, symbol: 'F', editable: false},
  {position: 10, name: 'Neon', weight: 20.1797, symbol: 'Ne', editable: false},
  {position: 11, name: 'Sodium', weight: 22.9897, symbol: 'Na', editable: false},
  {position: 12, name: 'Magnesium', weight: 24.305, symbol: 'Mg', editable: false},
  {position: 13, name: 'Aluminum', weight: 26.9815, symbol: 'Al', editable: false},
  {position: 14, name: 'Silicon', weight: 28.0855, symbol: 'Si', editable: false},
  {position: 15, name: 'Phosphorus', weight: 30.9738, symbol: 'P', editable: false},
  {position: 16, name: 'Sulfur', weight: 32.065, symbol: 'S', editable: false},
  {position: 17, name: 'Chlorine', weight: 35.453, symbol: 'Cl', editable: false},
  {position: 18, name: 'Argon', weight: 39.948, symbol: 'Ar', editable: false},
  {position: 19, name: 'Potassium', weight: 39.0983, symbol: 'K', editable: false},
  {position: 20, name: 'Calcium', weight: 40.078, symbol: 'Ca', editable: false},
];