import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { RegisterComponent } from "app/modules/register/register.component";


const routes: Routes = [
{
    path: '', pathMatch: 'full',
    component: RegisterComponent
}
];

@NgModule({
    imports: [
    RouterModule.forChild(routes),
    FormsModule,
    ReactiveFormsModule
],
declarations: [RegisterComponent],
    exports: [RouterModule]
})
export class RegisterRouter { }

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { RegisterRouter } from './register.router';


@NgModule({
    imports: [
      CommonModule,
      RegisterRouter
],
    declarations: []
})
export class RegisterModule { }

import { Component, OnInit, ViewContainerRef } from '@angular/core';
import { FormBuilder, FormGroup, Validators, FormControl } from '@angular/forms';

    @Component({
selector: 'app-register',
templateUrl: './register.component.html',
styleUrls: ['./register.component.scss']
})
export class RegisterComponent implements OnInit {

//#region Declarations
    UserForm: FormGroup;
    inValid: boolean = false;
//#endregion

constructor(
    private _fb: FormBuilder) {
    this.UserForm =  _fb.group({
    "_firstname" : ['', Validators.required]
    });
}
}

<input type="text" class="form-control" [ngClass]="{ahinValid: inValid}" id="txtFirst_Name" aria-describedby="ariaFirstName" placeholder="Enter First Name"
          name="_firstname" [formControl]="UserForm.controls['_firstname']">