title: Disable Input fields in reactive form
body: <p>I already tried to follow the example of other answers from here and I did not succeed! </p>
  
  <p>I created a reactive form (ie, dynamic) and I want to disable some fields at any given time. My form code:</p>
  
  <pre><code>this.form = this._fb.group({
    name: ['', Validators.required],
    options: this._fb.array([])
  });
  
  const control = &lt;FormArray&gt;this.form.controls['options'];
  control.push(this._fb.group({
    value: ['']
  }));
  </code></pre>
  
  <p>my html:</p>
  
  <pre><code>&lt;div class='row' formArrayName="options"&gt;
    &lt;div *ngFor="let opt of form.controls.options.controls; let i=index"&gt;
      &lt;div [formGroupName]="i"&gt;
        &lt;select formArrayName="value"&gt;
          &lt;option&gt;&lt;/option&gt;
          &lt;option&gt;{{ opt.controls.value }}&lt;/option&gt;
        &lt;/select&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I reduced the code to facilitate. I want to disable the field of type select. I tried to do the following:</p>
  
  <pre><code>form = new FormGroup({
    first: new FormControl({value: '', disabled: true}, Validators.required),
  });
  </code></pre>
  
  <p>not working! Does anyone have a suggestion?</p>