ngFor - Can't bind to 'testid' since it isn't a known property of 'input'. how to concat id with string?

问题

I am trying to add the index value with my ids. but getting an error as:

Can't bind to 'testid' since it isn't a known property of 'input'.

here is my template:

<td *ngFor="let col of columns; let i = index"  [ngClass]="col.class" data-testid="form-create-td-{{i}}">

what is wrong with my code? any one help me?

回答1:

I think you will need property binding. So please try to replace below testid data property.

<td ... [attr.data-testid]="'form-create-td-' + i">

For concatenation id property with string, you are doing right thing.

来源：https://stackoverflow.com/questions/58776401/ngfor-cant-bind-to-testid-since-it-isnt-a-known-property-of-input-how-t