mat-stepper every step in component

Question

I would like to implement a mat-stepper, every step is in a different component, my problem is to prevent the next button is clicked if the step is not completed:

parent.html:
<mat-horizontal-stepper>
  <mat-step [stepControl]="stepOneForm [completed]="stepOneForm?.valid">
    <ng-template matStepLabel>Step1</ng-template>
    <child-step-1 
       [stepOne]="stepOneForm"
       (stepOneEmitter)="updateStepOne($event)">
    </child-step-1 >
  </mat-step>
  <mat-step [stepControl]="stepTwoForm [completed]="stepTwoForm?.valid">
    <ng-template matStepLabel>Step2/ng-template>
    <child-step-2 
       [stepTwo]="stepTwoForm"
       (stepTwoEmitter)="updateStepTwo($event)">
    </child-step-2 >
  </mat-step>
</mat-horizontal-stepper>

parent.ts:
stepOneForm: FormGroup;
stepTwoForm: FormGroup;
 //////////
updateStepOne(step: FormGroup) {
    this.stepOneForm = step;
}

updateStepTwo(step: FormGroup) {
   this.stepTwoForm = step;
}

child-1.html
<form [formGroup]="stepOne" (change)="updateStepOne()">
   <mat-form-field>
    <input matInput required type="text" formControlName="title"/>
   </mat-form-field>
   <button mat-button matStepperNext><mat-icon>arrow_forward</mat-icon></button>
</form>
child-1.ts
this.stepOne = this.fb.group({
  title: ['Default title', [
    Validators.required
  ]]
});

updateStepOne() {
  this.stepOneEmitter.emit(this.stepOne);
}

Everything works but the stepControl, it is possible to go to next step even when the form is not valid.

Where is my mistake?

smithnblack smithnblack · Accepted Answer · 2019-09-12T16:29:58

You are using [stepControl] and [completed] at the same time. In this case stepControl is going to be interpreted as more important as [completed]. As stated in official documentation:

Alternatively, if you don't want to use the Angular forms, you can pass in the completed property to each of the steps which won't allow the user to continue until it becomes true. Note that if both completed and stepControl are set, the stepControl will take precedence.

Here is the link> https://material.angular.io/components/stepper/overview

mat-stepper every step in component

1 Answers