*ngIf and local template variables

Could someone please explain what’s behind the following behavior?

Say we have an Angular 2 component that has a _model object. Then in the template we have this:

    <input type="text" class="form-control" required [(ngModel)]="_model.firstName" ngControl="test2"  #myInput >
    <br>Class: {{myInput?.className}}

The _model is available from the beginning being created from scratch in ngOnInit(). The input field is properly populated with the _model.firstName variable and the line:

<br>Class: {{myInput?.className}}

correctly renders the following in the template:

Class: form-control ng-untouched ng-pristine ng-invalid.

So far so good. What confuses me is that the moment I add *ngIf and I change the input field to

<input *ngIf="_model" type="text" class="form-control" required [(ngModel)]="_model.firstName" ngControl="test2"  #myInput >

The double curly braces interpolation stops working because apparently the local myInput variable doesn’t get initialized even when nothing else in the code changes, the _model object is still created in onNgInit() and the input field is still working properly. The only thing that the {{myInput?.className}} renders is


Can someone explain what’s going on and/or point me to the correct piece of documentation for this?


Here’s a Plunker that shows the issue in question.

Created bug report https://github.com/angular/angular/issues/8087

Leave a Reply

1 Comment threads
0 Thread replies
Most reacted comment
Hottest comment thread
1 Comment authors
Jason Recent comment authors
newest oldest most voted
Notify of

We can reference a local template variable on the same element, on a sibling element, or on any child elements. — ref *ngIf becomes/expands to <template [ngIf]="_model"> <input type="text" class="form-control" required [(ngModel)]="_model.firstName" ngControl="test1" #myInput> </template> So local template variable #myInput can only be referenced inside the template block (i.e., sibling and/or child elements). Hence you would have to put any HTML that wants to reference the local template variable inside the template: <template [ngIf]="_model"> <input type="text" class="form-control" required [(ngModel)]="_model.firstName" ngControl="test1" #myInput > <br>Class (this works): {{myInput?.className}} </template> Plunker If you need to show something outside the template block related to… Read more »