Angular 4 - using objects for option values in a select list

Question

I know that similar questions have been asked, but I've found none with a good answer. I want to create a select list in an Angular form, where the value for each option is an object. Also, I do NOT want to use 2 way data binding. e.g. if my Component has these fields:

      lUsers: any[] = [         { Name: 'Billy Williams', Gender: 'male' },         { Name: 'Sally Ride', Gender: 'female'}         ];     curUser: any;  

I would like my HTML template to contain this:

      <select #selectElem (change)="setNewUser(selectElem.value)">         <option *ngFor="let user of lUsers" [ngValue]="user">             {{user.Name}}         </option>     </select>  

With this code, though, my setNewUser() function receives the contents of the selected user's Name field. Why it picks that specific field, I have no idea. What I expect is that it would receive the "value" of the selected option, which I specifically set to a user object.

Note that I used ngValue instead of value in the option. That was by suggestion of others on SO. If I use value instead, what happens is that the object gets converted to the string '[Object object]', which is what setNewUser() receives, which is useless.

FYI, I'm working on Windows 10, using angular 4.0.0 with @angular/cli 1.1.2. Here is the setNewUser() method:

      setNewUser(user: User): void {      console.log(user);     this.curUser = user;     } // setNewUser()  

I am determining just what exactly is being passed to it both my logging it, and also including this on the template: <pre>{{curUser}}</pre>

Answer 1

I'm currently using [ngValue] and it stores objects just fine.

The explanation as to why you experienced issues using (change) instead of (ngModelChange) can be found in this question

So, since you've already used [ngValue], you probably want to do something like this, where you will only use one way binding in order to be able to use the ngModelChange directive:

<select (ngModelChange)="setNewUser($event)" (ngModel)="lUsers">         <option *ngFor="let user of lUsers" [ngValue]="user">             {{user.Name}}         </option>     </select> 

And your ts file will capture the event and receive the User object without needing to track it by id, basically reusing your old method will be good enough:

setNewUser(user: User): void {     console.log(user);     this.curUser = user;     } 

UPDATE 16/06/2020:

Always depending on your use case you may need to use square brackets instead of round here: (ngModel)="lUsers. For the particular case the OP stated, round brackets was the right choice. A clear and detailed description of the difference between square/round and banana box can be found in this answer from Angular guru Günter Zöchbauer