How to accept values into array using Textbox and display the Sum of numbers using a Button?

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication8
{
public partial class Form2 : Form
{
int[] n1 = new int[3];

public Form2()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
//n1[0] = Int32.Parse(textBox1.Text);
//n1[1] = Int32.Parse(textBox2.Text);
//n1[2] = Int32.Parse(textBox3.Text);
//textBox4.Text = n1.Sum().ToString();

int value;

if (int.TryParse(textBox1.Text, out value))
n1[0] = value;
if (int.TryParse(textBox2.Text, out value))
n1[1] = value;
if (int.TryParse(textBox3.Text, out value))
n1[2] = value;
textBox4.Text = n1.Sum().ToString();


}
}
}