How to read form values in controller?

I am beginner in Angular 2 and I am trying get a value of textbox in component and I really don’t know how to get it.

HTML :

<form [formGroup]="regForm" >
                <label for="txtFName">First Name</label>
                <input type="text" id="txtFName"/>
</form>

component.ts :

import { Component } from "@angular/core"
import { FormControl, FormGroup, FormBuilder, Validator, Validators,ReactiveFormsModule } from "@angular/forms";
import { customer } from '../model/customerModel'
import { Router } from "@angular/router";

export class regComponent
{
    private Customer:customer;
    private regForm:FormGroup;
    private firstName:FormControl;

    constructor (private formBuilder:FormBuilder,private router:Router)
    {

        this.firstName=new FormControl('',[Validators.required])

        this.regForm=formBuilder.group({
        firstName:this.firstName
    })

console.log(this.regForm.value);
}

here I am getting empty value in the console. Please help in this regard

Answer

Add formControlName to input

<input type="text" id="txtFName" formControlName="firstName" />

Now access the value by name

this.regForm.get('firstName').value