angular2 + ionic2 - dynamic [attr.required]似乎不起作用

Question

I have a form with a input that is required only if the select.option != 'more'.

I have this, as a test 1==1 for force required.

<ion-input id="price" type="number" value="" [ngFormControl]="price"  [attr.required]="1==1"></ion-input>

<ion-select id="type" [ngFormControl]="pricetype">
     <ion-option value="fix">fix</ion-option>
     <ion-option value="more">more</ion-option>
</ion-select>

When I inspect the input it shows required=true or required=false , and the input isn't required at all, never. But if I write only required , it works...

What i'm doing wrong?

Thanks :)

Answer 1

Currently these validators are only properly instantiated when the attributes are added statically like

<... required maxlength="5">

but not when they are set by Angular bindings.

See https://github.com/angular/angular/issues/7393