如何使用angular 6在mat-table中根据条件只显示几列？

import { Component } from '@angular/core';
import { MatTableDataSource } from '@angular/material';

@Component({
  selector: 'app-my-table',
  templateUrl: './my-table.component.html',
  styleUrls: ['./my-table.component.css']
})
export class MyTableComponent {
  displayedColumns: string[] = ['column1', 'column2', 'column3', 'column4']; // 列名
  dataSource = new MatTableDataSource<any>(yourDataArray); // yourDataArray是你的数据源数组
}

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

  <!-- 根据条件动态设置列的显示 -->
  <ng-container *ngIf="condition1; then showColumns1; else hideColumns1;"></ng-container>
  <ng-container *ngIf="condition2; then showColumns2; else hideColumns2;"></ng-container>

  <!-- 显示的列 -->
  <ng-template #showColumns1>
    <mat-header-cell *matHeaderCellDef>Column 1</mat-header-cell>
    <mat-cell *matCellDef="let element"> {{element.column1}} </mat-cell>
  </ng-template>

  <ng-template #showColumns2>
    <mat-header-cell *matHeaderCellDef>Column 2</mat-header-cell>
    <mat-cell *matCellDef="let element"> {{element.column2}} </mat-cell>
  </ng-template>

  <!-- 隐藏的列 -->
  <ng-template #hideColumns1>
    <mat-cell *matCellDef="let element"></mat-cell>
  </ng-template>

  <ng-template #hideColumns2>
    <mat-cell *matCellDef="let element"></mat-cell>
  </ng-template>

  <!-- 其他列... -->

</mat-table>