How can I check if a mat-menu in Material Angular is open?

Question

I'm looking for a way to check if my mat-menu is open so I can add a class to the button that opened it using [ngClass] based on the state of the menu.

<button mat-stroked-button mdbWavesEffect [matMenuTriggerFor]="menu">Actions</button>
    <mat-menu #menu="matMenu" [overlapTrigger]="false" panelClass="custom">
        <a routerLink="/attendence/detail" mat-menu-item>View Attendance</a>
        <a routerLink="/adherence/detail" mat-menu-item>View Adherece</a>
        <button mat-menu-item>Edit Agent</button>
        <button mat-menu-item>Upload photo</button>
        <button mat-menu-item>Deactivate Agent</button>
    </mat-menu>

Solution 1

You can use Material matMenuTrigger directive to check whether the menu is open or not

<button mat-button [matMenuTriggerFor]="menu"   #t="matMenuTrigger">Menu</button>
<mat-menu #menu="matMenu">
  <button mat-menu-item>Item 1</button>
  <button mat-menu-item>Item 2</button>
</mat-menu>
{{t.menuOpen}}

Check the example here: https://stackblitz.com/edit/angular-9hbzdw

Now you use ngClass binding to change the style of your button!

Solution 2

I faced the same suituation. And I made a CSS work around.

While we click on the menu a custom aria tag is appended to the menu and get removed while we close the dropdoen. With this we can use CSS custom selector (It works with most mordern browsers)

.parentclass a[aria-expanded] { whatever you need }

Some case (if button)

.parentclass button[aria-expanded] { whatever you need }

Thanks,

Solution 3

You can bind your method on "menuOpened", that method will be invoked whenever Menu is opened

<mat-menu #menu="matMenu" [overlapTrigger]="false" (menuOpened)="isOpened($event)" panelClass="custom">
                    <a routerLink="/attendence/detail" mat-menu-item>View Attendance</a>
                    <a routerLink="/adherence/detail" mat-menu-item>View Adherece</a>
                    <button mat-menu-item>Edit Agent</button>
                    <button mat-menu-item>Upload photo</button>
                    <button mat-menu-item>Deactivate Agent</button>
                </mat-menu>

And add this method in your component,

isOpened(evt:any){
// set you flag here that you can use in ng-class for the button.
}

Hope this helps.

Solution 4

 <button mat-stroked-button mdbWavesEffect [matMenuTriggerFor]="menu">Actions</button>
            <mat-menu #menu="matMenu" [overlapTrigger]="false" panelClass="custom">
                <a routerLink="/attendence/detail" mat-menu-item>View Attendance</a>
                <a routerLink="/adherence/detail" mat-menu-item>View Adherece</a>
                <button [ngClass]="selectedMenuItem ===1 ? 'active' : ''" (click)="onSelectMenuItem(1)" mat-menu-item>Edit Agent</button>
                <button [ngClass]="selectedMenuItem ===2 ? 'active' : ''" (click)="onSelectMenuItem(2)" mat-menu-item>Upload photo</button>
                <button [ngClass]="selectedMenuItem ===3 ? 'active' : ''" (click)="onSelectMenuItem(3)" mat-menu-item>Deactivate Agent</button>
            </mat-menu>

selectedMenuItem = 1 // Initial value set to 1 onSelectMenuItem(id): void { this.selectedMenuItem = id; }

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Comments

[IvanS95]

I tried this solution, but as soon as my view is ready I just get an "Undefined" result, I'm outputting the value of "menuOpen"

[Chellappan வ]

did you add template refrence

[IvanS95]

Yes, If I just output the value of t.menuOpen in my HTML like you did: {{ t.menuOpen }} -- I get the "true" and "false" values as intended, but I can't use that value to evaluate a condition to pass to the ngClass directive

[Chellappan வ]

Can you share your code are you using ViewChild ot something?

[IvanS95]

Got it to work! It does seem it had something to do with my syntax. I just started to test using other directives and finally got ngClass working, thank you. [ngClass]="{'active':t.menuOpen === true}" I was missing the single quotes on the class name

[Patronaut]

Even easier would be to use [class.open]="t.menuOpen".