在Angular Material表中混合静态和动态列(mat-table)

你们有没有人知道是否可以在mat-table中混合动态和静态列？我用它来显示用户数据,但是我需要另一个列来显示关于用户的不同操作按钮.简单地添加另一个ng-container不起作用,因为在displayedColumns中没有列定义,但是当我添加它时,我得到“重复错误”.

<div class="example-container mat-elevation-z8">
<div class="example-header" layout="column" flex="100">
    <md-form-field floatPlaceholder="never">
      <input mdInput #filter placeholder="Filter users">
    </md-form-field>
    <span class="fill-space"></span>
    <button align="right center" md-raised-button color="primary" (click)="clearFilter()">Clear</button>
  </div>
<md-table *ngIf="users && displayedColumns" #table [dataSource]="dataSource">

  <ng-container *ngFor="let set of displayedColumns" [mdColumnDef]="set">
    <md-header-cell *mdHeaderCellDef> {{set}} </md-header-cell>
    <md-cell *mdCellDef="let element"> {{getValue(set,element)}} </md-cell>
  </ng-container>

  <ng-container mdColumnDef="akcje">
    <md-header-cell *mdHeaderCellDef> Akcje </md-header-cell>
    <md-cell *mdCellDef="let element"> asdf </md-cell>
  </ng-container>  <------ this doesn't show another column,when added to displayedColums,produces error

  <md-header-row *mdHeaderRowDef="displayedColumns"></md-header-row>
  <md-row [ngClass]="{'active-user' : current && element.Id == current.Id}" *mdRowDef="let element; let row; columns: displayedColumns;" (click)="gotoUser(element)"></md-row>
</md-table>

<!-- Generic column definition -->
<ng-container *ngFor="let column of columns" [matColumnDef]="...">
  ...
</ng-container>

<!-- Special extra column -->
<ng-container matColumnDef="myExtraColumn">
  ...
</ng-container>

/** Table columns */
columns = [
  ...,...,];

/** List of columns to display in which order */
displayedColumns = this.columns.concat(['myExtraColumn']);