为什么txt无法添加

Question

初学c#,大家帮帮忙！
目的简单，就是点一个button，往txt里添加一条记录。可是，下面的程序怎么一直是覆盖记录啊……
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        
        
        public Form1()
        {
            InitializeComponent();
        }        private void button1_Click(object sender, EventArgs e)
        {
            try
            {                FileStream aFile = new FileStream(@"D:\银行.txt", FileMode.OpenOrCreate);                StreamWriter sw = new StreamWriter(aFile);
                sw.WriteLine(textBox1.Text);
                textBox1.Text = null;
                               sw.Close();            }            catch (IOException e)
            {                Console.WriteLine("An IO exception has been thrown!");                Console.WriteLine(e.ToString());                Console.ReadLine();                return;            }
        }
    }
}

Answer 1

   sw.WriteLine(textBox1.Text,true); 

Answer 2

StreamWriter sw = File.AppendText(Server.MapPath(".")+"\\A.txt"); 
sw.WriteLine("AAA"); 
sw.WriteLine("BBB"); 
sw.Flush(); 
sw.Close(); 

Answer 3

默认就是ture吧，无效，还是没有添加，只是覆盖啊

Answer 4

using (StreamWriter sw = File.CreateText(@"D:\银行.txt", )) 
            {
               sw.WriteLine(textBox1.Text); 
            }

Answer 5

错了是using (StreamWriter sw = File.AppenText(@"D:\银行.txt", )) 
            { 
              sw.WriteLine(textBox1.Text); 
            }