dialog.component.ts

import { Component, OnInit, Inject } from '@angular/core';
import { MatDialogRef, MAT_DIALOG_DATA } from '@angular/material';
import { Validators, FormBuilder, FormGroup } from '@angular/forms';

@Component({
  selector: 'app-dialog',
  templateUrl: './dialog.component.html',
  styleUrls: ['./dialog.component.scss']
})
export class DialogComponent implements OnInit {
  public form: FormGroup;
  constructor(public dialogRef: MatDialogRef<DialogComponent>,
    @Inject(MAT_DIALOG_DATA) public data: any, private fb: FormBuilder) {
  }

  ngOnInit() {
    this.form = this.fb.group({
      remark: [null, Validators.compose([Validators.required])],
    });
  }
}