I have a complex MatMenu with more MatMenuItem. Each MatMenuItem's visibility is based on a condition. The trigger button is disabled if all possible condition are false, eg.:

<button mat-button [matMenuTriggerFor]="menu" [disable]="!condition1 && !condition2 && !condition3 && !conditionN">Menu</button>
<mat-menu #menu="matMenu">
  <button mat-menu-item *ngIf="condition1">Item 1</button>
  <button mat-menu-item *ngIf="condition2">Item 2</button>
  <button mat-menu-item *ngIf="condition3">Item 3</button>
  ...
  <button mat-menu-item *ngIf="conditionN">Item N</button>
</mat-menu>

There are a simple way for check if a MatMenu has at least one MatMenuItem and disable the trigger button if no one MatMenuItem are available?

CodePudding user response：

Issue with items

As mentioned in previous answer, one potential solution could be to use items of exported matMenu.

But we will have 2 issues :

• items property is

  CodePudding user response：

  Update please check the Thierry Falvo's answer

  I feel that the best bet is instead using condition1,condition2,... You can use an array disabled or an array of object to create your mat-menu (*)

  menus=[{title:'item 1',disabled:false,action:1},
        {title:'item 2',disabled:false,action:2},
        {title:'item 2',disabled:false,action:3}
         ....
       ]
  
  <button mat-button [matMenuTriggerFor]="menu" [disable]="disableMenu">Menu</button>
  <mat-menu #menu="matMenu">
    <ng-container *ngFor="let menu of menus" 
    <button mat-menu-item *ngIf="!menu.disabled" 
           (click)="doSomething(menu.action)">
          {{menu.title}}
    </button>
  </mat-menu>
  

  You can use a getter like

  get disableMenu()
  {
     return this.menus.find(x=>!x.disabled)?false:true
  }
  

  Or instead of use a getter use one variable and when you any object of the array menus equal the variable to this.menus.find(x=>!x.disabled)?false:true

  (*) the main problem I see in others approaches are that really the "menu" is in an cdk-overlay-container layer and it's difficult check it

  a stackblitz