How to set default selected values in multiselect with ngModel in Angular 2

Question

How to set default selected values in multiselect. I get current_options and all_options from database and I want to update current_options and send new values do database again.

Updating database works but when I refresh page none of options are selected.

current_options = [{id:1, name:'name1'}];                    #from database
all_options = [{id:1, name:'name1'},{id:2, name:'name2'}];   #from database

My template:

<select multiple name="type" [(ngModel)]="current_options">
    <option  *ngFor="let option of all_options" [ngValue] = "option">
        {{option.name}}
    </option>
</select>`

Answer 1

If you want create multiple select and option with ngModel and set default value and two way bind its working code

<div  *ngFor="let options of optionsArray; let in = index">
 <br>
 <select [(ngModel)]="res[in]" >
 <option  [ngValue]="option" *ngFor="let option of options.options; let i =index">


{{option}}
</option>
</select>
 {{res[in]}}
</div>
{{res}}

export class ExComponent implements OnInit {
public res=[];
 public optionsArray = [
   {id: 1, text: 'Sentence 1', options:['kapil','vinay']},
   {id: 2, text: 'Sentence 2', options:['mukesh','anil']},
   {id: 3, text: 'Sentence 3', options:['viky','kd']},
  {id: 4, text: 'Sentence 4', options:['alok','gorva']},
]
ngOnInit() 
{
this.optionsArray.forEach(data=>{
 this.res.push(data.options[0]);
})
}