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angularangular2-forms

Angular 2 FormGroup Add Validators dynamic

i'm tring to add validator to FormContol dynamic (not on initialization) and it's not work....

the code: 

this.formGroup.controls["firstName"].validator = Validators.Required;

Did anyone do it?

Solution

  • Try this, it should work

    this.formGroup.controls["firstName"].setValidators(Validators.required);

    For multiple validators

    this.formGroup.controls["firstName"].setValidators([Validators.required, Validators.minLength(2)]);

    But doing so will override any validators that are provided during initialization

    EDIT :

    To reflect the form controls with newly added Validators immediately, we have to call this.formGroup.controls["firstName"].updateValueAndValidity(); after setting validators dynamically.

    this.formGroup.controls["firstName"].setValidators(Validators.required);
this.formGroup.controls["firstName"].updateValueAndValidity();

    DEMO for the same

    * NOTE *

    updateValueAndValidity() will trigger a valueChanges event even if the value didn't really change (potentially resulting in an infinite loop, if you're calling it from within a valueChanges subscription). You can prevent that by using the optional parameter object: { onlySelf: true, emitEvent: false}