how do I save the text entered in a windows form to a text file? data is nt appending in text file

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C#

C#4.0

I am trying to develop an windows form application which accepts the input data like the data entered in textboxes, radio buttons selected etc., and save that data into a text file. It worked but the data is not appending in that file,it is replacing.

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;
using System.IO;

namespace fb
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            StreamWriter ws = new StreamWriter("C:\\File.txt");

            //sw.Write(String.Join(Environment.NewLine, listBox1.Items));
            //textbox
            ws.Write(String.Join(Environment.NewLine,"Name : "));
            ws.WriteLine(String.Join(Environment.NewLine,textBox1.Text));

            ws.WriteLine(String.Join(Environment.NewLine,"Responses are "));

            //q1
            ws.WriteLine(String.Join(Environment.NewLine,"For q1 : "));
            if (radioButton1.Checked)
            {
                ws.Write(String.Join(Environment.NewLine,radioButton1.Text));
            }
            else
            {
                ws.Write(String.Join(Environment.NewLine,radioButton2.Text));
            }
            ws.WriteLine(String.Join(Environment.NewLine,"\n"));

            //q2
            ws.WriteLine(String.Join(Environment.NewLine,"For q2"));
            if (radioButton3.Checked)
            {
                ws.Write(String.Join(Environment.NewLine,radioButton3.Text));
            }
            else if (radioButton4.Checked)
            {
                ws.Write(String.Join(Environment.NewLine,radioButton4.Text));
            }
            else
            {
                ws.Write(String.Join(Environment.NewLine,radioButton5.Text));
            }
            ws.WriteLine(String.Join(Environment.NewLine,"\n"));



            //saving
            ws.Close();
            MessageBox.Show("saved.");
        }
    }
}

here's the screenshot:
http://s0.uploads.im/QLZ7W.jpg[^]