How to prevent Dialog opening twice in angular material using angular5

Answer 1

when selection change event pass in every option, so got more then one event. but you got $event.source.selected is true in one event which is you selected. so you can manage it.

your html should be like

<mat-autocomplete #auto="matAutocomplete">
                <mat-option *ngFor="let person of filteredPersons | async" [value]="person.name"
                            (onSelectionChange)="selectedPersonsInDialog($event.source.selected,person)">
                    <img style="vertical-align:middle;" aria-hidden  src="{{person.imgUrl}}" width="30" height="30"/>
                    <span>{{ person.name }}</span>
                    <small>ID: {{person.id}}</small>
                </mat-option>
            </mat-autocomplete>
            <mat-autocomplete #auto="matAutocomplete">
            <mat-option *ngFor="let person of filteredPersons |  async" [value]="person.name"
                        (onSelectionChange)="selectedPersonsInDialog($event.source.selected,person)">
                {{person}}
             </mat-option>
        </mat-autocomplete>

your component function should be like

selectedPersonsInDialog(isSelected: boolean,person){
if(isSelected){
   this.selectedPerson=person;
   alert(this.selectedPerson); 
   let dialogRef = this.dialog.open(AddListOfPersonDialog, {
      width: '500px',
      data: { person:this.selectedPerson}
    });
  }
}