How to open all nested mat-expansion-panel? It only open in the first panel in nested mat-expansion-panel.

  openAllTab1() {
    this.accordion.openAll();
  }

stackblitz Link

CodePudding user response：

Because you are trying to open the Outer Mat Expansion Only. To open the nested ones You'll have to get its reference and call the openAll() function on it as well. Also, the multi input for the nested one should be true as well, as You want to open Multi Tabs.

I updated the stackblitz: https://stackblitz.com/edit/angular-nxv4vc-swren8?file=src/app/expansion-steps-example.html,src/app/expansion-steps-example.ts