I have two components Parent and Child.

Parent stores the state of the formGroup used in the child component. Each time I receive new data from external source, I pass this data through template and construct new FormGroup and decide based on one property if FormGroup is enabled or disabled. New data are changed as I want but the disabled/enabled state does not.

My code:

Child component

@Input() edvForm: FormGroup;
@Input() isBlocMainSupport: boolean;
@Input() data: Data;

ngOnChanges(changes: SimpleChanges): void {
   this.setForm();
}

setForm() {
   ...
   this.edvForm.addControl(
      'supportType',
      new FormControl({ value: supportType, disabled: !this.isBlocMainSupport })
   );
}

Parent component

edvForm: FormGroup;
isBlocMainSupport = true;
data: Data;

...

ngOnInit(): void {
   this.sourceEvent$
      .pipe(takeUntil(this.destroy$))
      .subscribe(newData => {
        this.newGraphicElements([newData]);
      });
}

...

newGraphicElements(newData: Data[]) {

   this.reset();
   ...
   this.data = newData[0];
   this.isBlocMainSupport = myCondition ? true : false;
}

...

reset() {
   this.edvForm = new FormGroup({});
}

Parent template

<child-comp
   *ngIf="isTheRightChild"
   [data]="data"
   [edvForm]="edvForm"
   [isBlocMainSupport]="isBlocMainSupport"
></child-comp>

To resume, data are well passed and change everytime as needed. But, disable state is not applied with : "disabled: !this.isBlocMainSupport"