use disabled mat form field code example

Example 1: mat input disabled

<mat-form-field>
    <input matInput [formControl]="inputFormControl"/>
</mat-form-field>

class YourComponent {
    inputFormControl = new FormControl({ value: null, disabled: true });
    
    this.inputFormControl.disable();
    this.inputFormControl.enable();
}

Example 2: how to disable mat-form-field in angular 8

If you are using a FormGroup, then you should not disable the form in the HTML Template. It will not work if you try to disable in HTML together with FormControl. Instead, it should be done within the FormGroup. Try this:

  template: `
    <mat-form-field [formGroup]="form">
      <input matInput placeholder='Name' [formControlName]="formControlName">
    </mat-form-field>
  `
and:

ngOnInit() {
    this.form = this.fb.group({
        name: new FormControl({ value: '', disabled: this.disabled })
    });
}
Also...not a big deal but..you should really be doing:

public form: FormGroup;
instead of:

public form: any;
Don't forget the import as well

import { FormGroup, FormControl } from '@angular/forms';
Btw, the name inside of the form group declaration should match whatever you have set in the HTML. So:

<input formControlName="myInputName">
and

this.form = this.fb.group({
    myInputName....
});